Top Tips to Get Your Home Ready for Winter

Almost overnight the mornings now have a distinct chill, the evenings are already getting darker earlier; and the warmth of the summer sunshine is becoming a distant memory.  As the evenings start to draw in, it’s time to start looking at your home and garden to see what needs organising before the chill sets in and how to make it cosier and work more efficiently for you.

Summer versus Winter
In the Summer it’s all about connecting with our outside space and spending as much time outside enjoying our gardens, patios and decking. Blinds are used to keep rooms cool and we use air-conditioning and fans in the really hot weather. However, as it cools down the opposite is true with windows being closed (also to try and keep the many spiders out) and central heating and fires being lit to warm our homes.

Move your furniture
In the warmer seasons; we tend to turn our furniture more towards the windows to enjoy the sunshine coming in, with our windows and doors all left open to let the fresh air in.  However, in the winter months furniture is rearranged for a cosier feel centred around the fireplace or another central focal point. Make sure you move any furniture away from radiators to maximise the heat coming out.

Roof ventilation
In the Summer months, the roof space can literally bake and if there is nowhere for that heat to go it will build a stack of hot air in the roof which will eventually force itself into your living space from the ceiling down. It is essential therefore, to install just enough ventilation to stop the stacking effect.  In the winter months; you have the opposite problem of all your heat rising into the loft, so it is recommended to consider insulation in the loft to stop the heat rising and the cooler loft space impacting on your downstairs space.

Adjust your thermostat
It is suggested that in some circumstances for each degree you turn down the thermostat towards the outside temperature you reduces your heating costs and greenhouse emissions by roughly 10%. Make sure though that your boiler is in tip-top condition and has been serviced within the last year to make sure it is not only safe to use but working as efficiently as possible. Bleed any radiators to make sure they are working properly.

Get snug with textiles and textures
When it starts to get chilly; we dig out our jumpers and cosy socks but the other way to keep warm and make your home look cosy is through the use of textiles and textures. You can introduce more fleeces and fake fur throws into your home to put on the sofa; along with cushions in cosy fabrics like chenille to keep yourself snug of an evening and the heating down lower.

Check for any gaps
It is a good idea to check around your doors and windows for any significant gaps and seal them to keep any drafts out (and spiders).

Close your doors
Make sure you don’t leave all your doors open, so therefore, close the doors to rooms you do not use which thereby reduces the area to keep cool or warm.

Use Compact Fluorescent Light bulbs (CFLs)
These bulbs use 75% less energy and produce 75% less heat than incandescent light bulbs which will save you money as well on cooling. Also consider LED lights as they are often cheaper and easier to retrofit. It is a good idea to consider brighter bulbs for those darker days but make sure they are energy efficient where possible.

If you can get your family members into the habit of wearing a jumper and similar warm clothes; you will save a fortune in heating costs. You will be using your own body heat to help keep you warm, so allowing you to reduce the heating thermostat.

Use an electric blanket at night
If you don’t like a hot bedroom but still get a bit chilly, why not use an electric blanket or go old school and bring out your hot water bottle which means not having to heat the whole bedroom.

Put your Summer clothing away
Once the last of the sunshine has gone, put your summer clothing into the loft to make more room for warmer winter clothing.

Tidy your garden space
When it comes to your outside space, make sure you put your garden furniture away that is susceptible to wet weather (or frost) and could potentially crack.  Look at bringing any plants inside that can’t cope with winter or cover them with protective sleeves. 

Give your windows one last clean
Autumn is a good time to have one last clean of your windows before the bad weather sets in. It also gets rid of some of the many spider’s webs and nests that have appeared towards the end of the summer.

We hope some of these tips have been useful to help you organise and transform your home ready for the Winter 😊

How Clerestory Windows Can Bring Light to the Darkest Home

If you need to bring more light into your home without losing valuable wall-space, Clerestory windows could be the answer to your prayers.  Although mainly seen in the commercial sector or in contemporary/smart houses and apartments, these little gems are windows at high level (above your eye line). They are often used by architects and designers producing individual homes for self-builders but despite this, many aspiring self-builders do not actually know what they are.

The term ‘Clerestory’ was originally applied to the wall containing the windows above the nave (that’s the middle bit often incorrectly called the Aisle). So believe it or not, the Bride and Groom do not actually come down the aisle, they come down the nave! The windows created light and airiness in our magnificent cathedrals, which is exactly what the architects were trying to achieve. As the building technology developed to create bigger and bigger openings in the structure, the amount of opaque glass got larger and more impressive.

The main aim was to impress and show off to other cities just how technologically advanced they were. However, there is no doubt we are still impressed, even today, by so called curtain glazing or perhaps a well-placed little window that just manages by its position and orientation to allow some light to infiltrate into the otherwise darkest vestige of a house.

As house designers, it is this type of clerestory window that we are interested in because that little chink of light can be so effective in contemporary interior design. It can be unexpected, it can cast shadows picking up the sculptural nature of the structure and it can carry inside the mood of the day. Therefore, connecting you with the early morning sun, the turbulent sky or the hues of the setting sun.

From a practical standpoint, clerestory lighting can be useful to avoid overlooking in compact cities and it is the height of a window that determines how far light will penetrate into an otherwise gloomy room. Even with ordinary eye level windows, the width of the window will determine the light intensity in the room near the window. If you want the light to penetrate in then it is the height of the window that is important. There is also something to be said for orientating the clerestory window northwards because north light is more consistent. It also does not cause glare one minute requiring the blinds to be drawn and dinginess the next, making it necessary to turn the light on.

The other advantage in using north light is that solar gain and over-heating will not be a problem. Beware of using too much glass inclined to the south facing sky because of overheating. You will not need such a big glass area anyway because the light that they will allow in is much more effective than the equivalent window area. Lastly you may wish to avoid roof lights in bedrooms unless you are a very sound sleeper as hail hitting glass is very noisy and can be quite scary.

Another useful feature of a clerestory window is when your self-build or new extension is often overlooked on one side by an ugly wall or other feature belonging to the adjoining house that is very close to you. Therefore, it will provide light at a high level but the narrow size of the window will mean that the ugly feature can hardly be seen.

Clerestory windows are also useful on single storey houses when there is a projection outside the building in the form of a corridor; which is used to get from the front to the rear of a long, thin single storey house. A clerestory window therefore, can help counter the effect of the corridor by reducing the amount of light that enters the house.

When it comes to first floors on houses, you will often find a clerestory window tucked under the roof at the head of a staircase. Many architects feel that staircases often end up depending on artificial light and therefore, if they are properly lit, they can become much more of a feature. Additionally; many architects like to tuck an upstairs clerestory window under the eaves; as you have no external wall structure above that has to be supported by the window frame.

High level windows if fitted with the means to open can be a real joy to allow stale air out of a living space.  Drafts can be avoided and, as heat rises, a natural flow of air will circulate upwards, pulling cool and fresh air in from outside. That is if the space is designed with this in mind of course.

If you would like more information on how clerestory windows could work in your current home or proposed self-build home, please do contact Building Tectonics as we will be only too pleased to advise you.

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Green Design, Green Upkeep: Building and Maintaining Your Environmentally-Friendly Home

Residing in an energy efficient building not only lowers your utility bills, but can add an average of 14% to your home’s value, meaning it is not only good for the environment, but also beneficial for you as the homeowner. When setting out to build a green home, there are several factors to take into account, but the most important one to keep in mind is that a green home needs to be treated as such, from inception and throughout its lifetime.

The first, and perhaps most important, step in building a green home is a design conducive to environmentally favourable construction. A green home is much more than simply designing the living spaces, but must also account for the mechanical systems and materials used to qualify as a green construction. Once you have your design in place, you can move on to choosing which green materials will make your home as efficient as possible.

Sustainability is Key
Choosing sustainable products is one of the most important aspects of constructing a green home. You’ll want to make sure you select building materials that are certified as such by a specialist organisation and to research those materials in terms of eco-friendliness and stability in the long term. For the larger portion of the construction, you’ll need to procure sustainably forested timber, and perhaps to look into a roofing material that can be recycled or repurposed at the end of its life cycle.

For the interior of the home, there are many green products that are aesthetically as lovely as anything else on the market. From flooring and skirting boards to countertops and backsplash tiles, there are a multitude of sustainably produced, recycled or recyclable, and re-purposed materials to select from that will fit any style. With green building being so popular now, manufacturers are quick to disclose such properties and advertise themselves as appropriate for ecological construction.

Pay More Upfront
Energy efficiency is one of the main components to green building and you’ll want to take this into account in all aspects of the home, from windows to mechanical systems. High efficiency systems may cost more upfront, but will save you energy and money in the long term, eventually paying for themselves. Many of these systems will come with a guarantee, and the manufacturers will have already done the maths on your projected savings over the life of the home, so you’ll quickly be able to see how much you’ll save.

A Finished House Isn’t the End
Once you’ve completed a sustainable, green home, you have to keep in mind that environmentally-friendly maintenance must be part of the plan. Some of this maintenance should factor into the home design, especially in terms of landscaping. You’ll want to select plants and grasses that are native to the area, therefore, requiring less water and fertilisation. Additionally, you’ll want to explore some eco-friendly cleaning solutions, as many cleaners use harsh toxic chemicals that can be damaging to the environment.

Committing to a home that is environmentally responsible is one that will last a lifetime. The process may be challenging, but keeping your goals and reasons for undertaking such a project is key. The financial commitment upfront may save you some money in the long run, but it will take more effort and money to bring your green home dreams to life, and to maintain it thereafter.

Designing and maintaining a zero-energy home takes a lot of thought and consideration as well as a know-how on the best way to get the most out of the technology involved. Technology is rapidly changing which means that the trends of today are often out of favour a few years later. Government subsidies and schemes can play a big part of how well companies market their preferred product in terms of benefits, efficiency and cost so it is important to do your research.

The bulk of the battle to become zero-energy often lies with simple aspects such as making sure the building is well insulated and air-tight. Thought should also be given to the orientation of the building in relation to the sun; as natural light can help reduce energy bills in terms of lighting, heating and cooling. Using some form of brise-soleil (an architectural feature of a building that reduces heat gain within that building by deflecting sunlight) can prevent overheating in the summer; whilst still gaining the warmth and light from the low winter sun. Trees that provide shade can also help.

Moving onto the technology side of things, there are many routes available that each have their benefits and drawbacks. Where energy is sourced from is perhaps the main hurdle to overcome. Whilst solar panels are one of the more well-known ways of reducing energy costs, other alternatives to look at include Micro CHP boilers, air source and ground source heat pumps. Upgrading appliances to more energy efficient ones is often overlooked. Mechanical Ventilation Heat Recovery can remove stale air whilst retaining some of the heat which transfers to the fresh air entering the building which reduces the amount of heating required.

Team Trip to Kingspan to Learn about Timber Frame Housing

It is always very productive and a change of scene; to get the Building Tectonics team out of the office together to learn more about particular areas that we work on.  So, on Thursday 14th March we all went on a trip to Kingspan Potton, based in Great Gransden, Bedfordshire who specialise in fabricated timber frame housing.

The walls, floors and roof of the houses are fabricated in large panels in their factory and are then taken to site and bolted together to construct a house (or other types of buildings).  Although there are several companies who already work in this area; Kingspan have moved away from the mass housing market and instead of supplying the larger house builders, now just supply one or two units to small developers or even one-off houses.

On arrival the BTL team were greeted in the meeting room by the National Sales Manager; who gave a presentation about the different products they produce and then showed them around the factory where they are made. They saw how the process works from start to finish; from when the wood comes into the factory to when it leaves on the back of the lorry.  Following this, they drove 15 minutes away to the Potton Self-Build Show Centre in Little Paxton, near St Neots where they have 5 show-houses. The team had the opportunity to look around the show-houses; which showed them the different materials that Kingspan manufacture and the different structures that they are capable of producing.

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Kingspan can help with the design of any house and have a pattern book of designs you can choose from; but obviously being an Architectural Practice, we already do the design for our clients.  However, Kingspan can take our bespoke design plans and prepare “shop drawings” showing the panels so that they can then be fabricated in their factory. It was very interesting for the BTL team to know all about the process and the types of systems available; for those occasions when a client wishes to have a timber frame house.

There are alternative systems available from other timber frame fabricators: –

Open Panel Systems
The majority of timber frame companies use an open-panel system for the internal loadbearing of the cavity wall.  These are made in a factory from a softwood timber frame covered with a structural sheet material such as plywood or oriented strand board (OSB) and fixed into a structure on-site.  They have a waterproof membrane on the outside and are left open on the inside.  The windows and door frames are fixed on-site and when the house is watertight; the electrical and plumbing casing is installed and the insulation put in place finished off with a vapour-proof barrier and plasterboard.

Closed and Advanced Panels
These systems are used by most of the Scandinavian frame companies and are delivered fully furnished and insulated, with the services in and the windows and doors already fixed – with the advantage that it is an airtight structure that needs minimal on-site work. However, it does mean decisions need to be made early on in the design about services and outlets.

Green Oak Frame
This is the most traditional timber-frame building method and is often referred to as exposed timber frame. The oak is often jointed using mortise and tenon joints, draw-pegged with tapered oak pegs and then integrally braced with curved oak bends jointed into the frame.  Insulating panels are then infilled into the massive oak skeleton and it is made waterproof using a system of perimeter trims and water bars; before being rendered on the outside, leaving the timbers exposed.

SIP Systems
Structural insulated panels (SIPs) are high-performance building panels used in floors, walls, and roofs and are typically made by encasing a core of rigid foam plastic insulation between two structural skins of OSB, but other skin material can also be used.  The panels are manufactured under factory-controlled conditions and can be custom designed for each home.  SIPs are fixed to the outside of the timber frame, so the entire frame can be exposed in the interior or covered up, depending on the look you want to achieve.

Kingspan are first and foremost an insulation company and therefore, have naturally moved toward the highly insulated end of the market.  Timber frame housing can be extremely well insulated and this form of construction lends itself to the addition of a lot of insulation without making the walls unduly thick (unlike brick and block walls).  However, the really interesting development is the SIP technique as these panels can achieve incredible levels of insulation and therefore, are often found in zero energy projects where no heating is required; other than the heat that is created by simply inhabiting the house (possibly with the addition of some solar heating).

Building Tectonics have designed a couple of very low energy houses and are greatly interested in this area. SIP panels also offer really low air infiltration so therefore, help reduce heating bills and increase comfort as they avoid drafts and cold spots.  They can be very strong and rigid and can be used in floors and roofs; which is a real game changer in the construction of houses, but the building industry has generally not embraced this new technology.  Houses built like this can be erected on-site superfast incorporating all the services and the standard of finish can also be superior.

As a practice we would like very much to use this technology wherever we can; but the question is whether our clients will choose something brave and new.  The major practical difficulty is using prefabrication techniques for extending existing buildings, which is where most of our work lies. Ironically, the big problem would be bolting something so perfectly made (1 or 2 mm accuracy) on the side of an existing building where the building tolerances can often be measured on several centimetres. What we need are clients who can see the benefits of such new techniques and we stand ready to help in any such project should it arise.

A Day in the Life of an Architectural Practice

Have you ever wondered what it is like to work in an Architectural Practice for the day and envisaged all the dreaming and designing that goes on? Well now is your chance as we get inside the head of our Chief Designer, Tony Keller to find out what a normal day entails for him and the Building Tectonics team from start to finish.

Tony says “A normal day at Building Tectonics encompasses a number of different tasks but generally starts with a team briefing (accompanied by a cup of tea) to run through which stage we are at with each of our client jobs; to make sure everyone is up to speed and we know where our focus is for the day.

We make sure that any emails, telephone or Facebook messages that have come in overnight are responded to immediately; as we always try to reply within 24 hours where possible. If it is a new enquiry, I will ring the customer to find out more about them and what they are looking to achieve; and we arrange a time to meet them to see how we can help with their project.

Depending on what stage we are at with a particular job, one of the team may go out to a client’s house to get the accurate measurements of their home and also to measure their land boundaries.  It is vital these measurements are correct; as they are entered into our online system and used to draw up the existing plans, elevations and sections that will eventually be submitted to the Council Planning Department and thereafter the client’s builders. These measurements also start the process of drawing up the client design options and from time to time we also use them to produce 3D models for certain projects.

As a team we need to familiarise ourselves with Permitted Development Guidance, Planning Policies and Building Regulations for specific projects and a member of the team will fill in the Planning Application forms and deal with the queries from Planning Officers and third parties.  Detailed Building Regulations drawings will need to be drawn up and the site evaluated to look for any potential hindrances such as sewers, trees, flood risk areas, radon prevalence etc.  As part of this we will purchase and download Ordnance Survey mapping data for Planning Applications and other uses along with Drainage & Water Enquiry maps.

There is obviously a great deal of administration involved for the Building Tectonics team on a daily basis; as we respond to multiple emails and phone calls every day, scan all our client documentation onto our computer system and file all paper copies of projects as part of our audit trail. This then acts as our own Project Management tool to see where a particular project is at any time; and we conduct quarterly job reviews where we check the current status of every live project to make sure nothing gets missed at any stage.

With us being a hectic office, we need to make sure we don’t ever run out of any office stationary including printer ink, plotter rolls and paper as these are essentials for our office to run like clockwork (along with cups of tea!!).

It is very important that all of the team are up to date with the latest developments in the industry and any new changes to legislation, so we all attend regular CPD Seminars (Continued Professional Development) both during and outside of work hours and keep up-to-date on relevant industry news.

There is a great deal of research involved in design projects relating to anything from Planning, Building Regulations, construction problems, product information, Party Walls, Sewer build-overs to just general questions that we get on a daily basis from our clients.

Marketing is essential to all businesses to thrive and we try to regularly blog and share content that is of interest both to our current clients and potential new clients to update them on the industry and jobs we are currently working on.

Working in an Architectural practice, no single day is the same; but I really love working for myself.  I enjoy the variety of work it brings, the opportunities to meet new people and work with other professionals but most importantly seeing the happy faces of our clients when a job is finished. I always meet face-to-face to go through design drawings with my clients; as this is essential to ensure everything is covered to avoid any hiccups at a later stage of the project.  I thrive on being busy but obviously could not do it without the support of my committed team”.

Mixing the Bricks

You may have noticed tall brick walls can have bands of different shades of colour; this can be deliberate, a feature of the design specified by the architect, but it’s often a product of poor management. It’s becoming more common to see this “banding” in most new brick houses, it’s very rare to see this in old brickwork.One of the attractions of an old brick wall is the variation in the shades of brick as opposed to the somewhat clumsy but inadvertent banding in new buildings.

How can this be avoided? Care and attention of the bricklaying is the answer; not so long ago a bricklayer would have a labourer (or hod carrier) who would unpack and mix the different batches of bricks before carrying them up the scaffold on his hod. You seldom see a hod these days, because builders tend to use hoists to lift the bricks to the ‘upper lifts’ of the scaffolding. We’re all for the safety and efficiency when dispensing the hod carrier, but the loss of the old practice is very sad because it results in an unattractive banding, and patches of brickwork.

Brick banding happens because each batch of brickwork is different, this is because the clay coming out of the ground varies as they excavate down through the layers of clay. The firing process can also vary, causing the bricks to have a slightly different hue. If builders organise themselves and know how many bricks they need prior to brick delivery brick suppliers can mix them for you before delivering; if they don’t know the amount needed before ordering the bricks they could mix them themselves by taking some bricks from one batch and some from another.

Brick banding by design, this is an example of banding that was planned.

It would be a big improvement if more brickies would take further care over this aspect of building, and if clients are aware of this then they should insist on it as well. One word of warning; if you unpack and mix the bricks by hand, you’d need some protective eyewear because the brick dust is sharp and would therefore scratch the soft tissue of your eyeball very easily which would be incredibly painful.

Scratching the surface of Concrete.

Two billion metric tonnes are made worldwide annually, it’s also a very economic material so it’s used unsparingly. This wasn’t always the case and for a while, it was a material much loved by architects to be seen and revered. It is made from materials commonly found all over the world except the cement constituent. The Romans made a type of concrete but this knowledge was forgotten in the dark ages.

In 1824 Joseph Aspdin from Leeds made the first modern cement from pulverised limestone and clay which he then burnt and ground down into a powder. He named this “portland cement” because its colour resembled portland stone. It has a very good compressive strength which is durable and can be formed into complex shapes and sets at a wide range of temperatures. We now combine it with steel to increase its tensile strength which makes it an underrated wonder material of the modern age.

A type of modern architecture not in favour these days called Brutalism was coined not because it is somewhat brutal in appearance, but from the joining together of two French words, brut (the french word for raw) and béton the french for concrete, and this got corrupted into Brutalism.

Foundation Design

There are some new and interesting developments in foundation design which offer an alternative to the way we have been constructing foundations for the last few hundred years. At least so it seems. It would be interesting to look at these new developments in the context of the traditional ways of supporting a building.

Let’s consider what we expect from a foundation. It has to be able to spread the load so that the ground can support the load. It has to be stable so that it will not move around. Sometimes the foundations are used to anchor the building so that it will not overturn – this is particularly true of taller, lightweight structures such as timber frames houses.

A photo of pale stone foundations with a small set of stairs.
Image courtesy of Wiki Commons stock images.

So how do we achieve this? Spreading the load is not difficult except where the soil is very soft, and that is not usually the case in our area. Ensuring that there is no movement is more difficult as our clay in the South East of the UK is prone to shrinkage and heave caused by changes in the moisture content in the clay. For this reason, the minimum founding depth is usually a metre and much deeper if trees are nearby. Holding a building down sometimes has to be considered but by the time you have dealt with the other criteria, this holding down or overturning aspect can be shown to be resolved.

The way we spread the load of the building can be dealt with in a number of ways. The usual way is to dig a trench, fill it full of concrete and then build the load-bearing walls off of this. This is called a trench fill foundation (or footing as builders like to call it) where the concrete almost comes to the surface, or a strip foundation if the trench is only partly filled with concrete and then masonry is built up to the ground level. Sometimes we dig a series of holes which are filled with concrete and then beams span between. These ‘pad foundations’ as we call them require less excavation and soil to be taken from the site, and less concrete, but require additional structural elements above.

The above techniques account for 90% of low rise buildings in the UK whereas for the remaining 10% the solution is usually a piled foundation. Crudely, piles are either driven in or a hole is drilled in the ground and then filled with concrete. The piles will give intermittent support just like the pad foundations mentioned above, and so beams have to be used to span across the top to support the buildings walls. Where the hole in the ground is first created and then filled with concrete it is classed as a replacement pile, and where a steel element is driven into the ground it is called a driven pile. Further sub categorisation is made and they are described as short bored or deep bored piles.

Now this neatly brings us onto the first new innovation in the UK for many years. We now have a worm-screw type of foundation which could be described as a large steel screw and this is screwed into the ground where it becomes the support. It reduces the amount of spoil that has to be removed from site and can be installed in any weather.

Another new type of foundation is that promoted by Advanced Foundation Technology Ltd as advocated by Kevin McLoud of Grand Designs. Basically, this seems to rely on removing some soil and replacing it with a material that will not be affected by freezing conditions. I confess to not understanding how this deals with the shrinkage caused by changes in the moisture content of clay and so I will remain skeptical for now, but clearly in areas where the ground is affected by changes in temperature only, this could be effective.

Clearly the type of foundation your building designer or engineer chooses will be based on individual factors pertaining to your project, and the industry is notoriously conservative for not taking up new ideas but it will be interesting to see how these new ideas are taken up.

Written by Tony Keller – Building Tectonics Ltd

Roof trusses

Most modern house roofs use trussed rafters in the construction of the roof. They consist of quite slender pieces of wood, which are fixed together at the junctions with metal plates. The really clever thing about them is that they derive their strength from their geometry, which is always based on a system of triangles. The alternative way to construct a timber roof is for a carpenter to cut timbers on-site, to the correct length, and then nail them together. This process takes longer than unloading the ready-made trussed rafters from a lorry and positioning them on the house. Invariably, the size of the timbers in a cut, or framed up roof, as it is usually called are much bigger than the timbers used in a trussed rafter roof, this is because you cannot rely on the strength of the junctions to transmit the loads in the same way. In a trussed rafter, the metal plates used to join the timbers together have protruding ‘teeth’, which are forced into the wood by a press, and because this is done in a factory, the quality can be more precise than if you were to rely on a carpenter hammering nails in on the building site. Also, the wood used in trussed rafters is selected to ensure that the design strength is achieved. Apart from the economies in wood, and the time taken, the other significant factor is that the trussed rafter can often span considerably further than a traditional framed roof, often from one outside wall to the other outside wall, meaning the internal walls may not be load-bearing, which in turn means less foundations need to be constructed. All of this can result in large savings in house building costs.

There are of course some disadvantages. The resulting roof space will be a bit more cluttered due to the timber members forming the triangular geometry, and the trusses have to be handled and stored with care, as they can be easily be damaged. They can be more easily affected by wood rot than a cut roof because the timbers are smaller, however, it is now usual practice to have trusses treated with wood preservatives, which help to resolve this issue. In the past, the metal plates have also been known to suffer from corrosion, but these too are now treated to stop them from rusting – it may surprise you to know how the damp the internal space of a roof space can be, which is why we now ventilate roof spaces.

Another disadvantage of a trussed rafter roof is that they are usually (but not always) more difficult to convert to a useful space, like a bedroom. Here at Building Tectonics, we do the design for many loft conversions, and we have derived techniques for both types of roof. but generally a little more steel work is required for a roof consisting of trussed rafters. Of course, with a little forethought from the house builder, this can be overcome by using what we call “room in the roof trussed rafters”. These are more expensive than the alternatives, but still a lot cheaper than constructing the roof on-site out of timbers. It is a shame that more developers do not use the room in the roof trusses as it would allow many houses to later be given an additional bedroom more easily if they ever wanted to convert the space, but of course, house builders want to maximise their profit. Self builders should really consider spending the bit extra to give themselves that flexibility later. We usually do recommend this to clients, we have also had some past conversion/alteration projects where because of the drastic nature of the work, we have suggested that while the client is going to all this effort, they may as well remove the existing roof and replace it with room in the roof trusses. Even though taking a roof completely off is not for the faint hearted and can only be done after much preparatory work such as creating a temporary tent over the house, it is sometimes a brilliant success, it is also more often than not, a lot cheaper than many alternatives too.

The trussed rafter roof was a major innovation in the construction industry when they started being used more generally in the 1960’s. Once the early issues of rot and some manufacturing problems were overcome, the only real problem we are left with in their use is that they are not being handled on site with the care that they should be. They create a very strong roof when it is complete, but the slender nature of the wood elements makes trusses very susceptible to damage until they are in place, therefore good on-site management is required. Apart from the framed roof, and trussed rafter roofs, there have been some other types of roof structures formed in wood, one such system is often called a Trussed roof, this is where timbers are bolted together to form a very strong element, which is then used to support purlins and rafters, which can be smaller than those used in a corresponding framed roof. These were used a lot in in the post housing boom of the 1950’s, but even though they were more economic in timber (meaning that there was less timber involved) than the traditional framed roof, they still lost out to the even more efficient Trussed rafter.  However the terminology can cause some confusion when discussing older buildings, but since many (younger) builders have never seen such a thing, getting the terminology correct is now less important.

This is what one happy client wrote after we advised him of the benefits of using trussed rafters:

Thanks Tony for recommending I use prefab roof trusses on my loft conversion and extension. Not only did it give me the ability to have a much wider open plan kitchen family room but it was significantly cheaper. My builder quoted me 12k but I ended up paying just under 7k.

Written by Tony Keller – Building Tectonics Ltd.


Plywood is a simple, but effective material. This is used a lot in the world of construction due to its strong structure, but light weight. It’s quite a flexible material, not physically but in the sense that you can add many layers and make it as thick as you need.

Modern plywood as we know it was invented in the 1800’s. The famous two seater aircraft of World War Two, De Haviland Mosquito was mainly made of different grades of plywood. Furniture makers and Architects started using this material around the 20th century after the second world war when production of plywood became a bit more commercial, and also due to its economic value.

Plywood’s strength comes from the way in which it is made.

It is made up of different layers of veneer, with the inner layer being called the core, and the outer layers being called the faces. The number of layers included is always odd so that the faces look the same. This is good for objects which you’d see both sides of, like a door as it gives the illusion of it being one solid piece of wood rather than lots of layers stuck together.

Each layer is turned at a 90 degree angle from the last, this strengthens the structure of the product because the grains are going in different directions. It is then put together using glue. The type of glue depends on where the plywood will be used:

  • Interior – this type of plywood could be glued using either highly resistant glue which is fairly resistant to moisture in the air, or intermediate glue which is resistant to mould, bacteria and moisture. Neither should be used for exterior plywood though.
  • Exterior – This plywood is made using waterproof glue.

The plywood is then placed between two large hydraulic shelves and squeezed together whilst being heated to dry the glue, it can then be trimmed and sanded to give a better finish. The outer layers can be made of more expensive layers of wood to make it look better as they are usually thinner.

The more layers of veneer you have in the plywood, the stronger the structure will be and the more resistant to impact it will be, so that it won’t split, chip, crack all the way through or crumble. These layers also make it more resistant to shrinking, warping, twisting or swelling so much as ordinary wood.

You can get exact sizes and thickness’s when you buy plywood, which is handy if you’re on a budget, you’d only be paying for exactly how much you’d be using rather than having any waste.If you do buy plywood, be sure to look out for the initials APA (American Plywood Association), or DFPA (Douglas Fir Plywood Association) as these two companies represent most of the plywood manufacturers and test all plywood to ensure that the quality is to a high standard.

Written by Jade Turney – Building Tectonics Ltd.