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; and 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, but 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 thus 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; but if you want the light to penetrate 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 and 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, as you will not need such a big glass area anyway because the light, 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, as 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 as 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’s 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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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.

Success rate

One of the first things new clients ask us is how successful we are at getting planning approvals.

Other new clients can sometimes come to us because they have been clever enough to check out the planning permission success rates of architects, and architectural consultants in Milton Keynes themselves. When they do, they can see that our success rate is pretty good, and probably better than the competition.

One of our new clients had really done their homework – they told us that over the past 7 years, 96% of our domestic clients who have instructed us to apply for planning permission received a planning approval. Yes, 96%! Even we were astonished when we found out. You may be forgiven for thinking that we must only take on the easy projects, or that all of our projects are hidden away in back gardens, but no. We design quite a few front extensions for instance, and in some cases, other practices have tried and failed to obtain planning permission before us.

So what’s the secret?

Quite honestly, we do not know. It is not because Milton Keynes council are a pushover as they can be as picky as the next council, but we think it is partially because we put our schemes together with care.

Occasionally, we tell clients that what they are asking for is likely to be controversial and we try to steer them towards something more acceptable, we are pleased to say that in most cases they listen. Most clients are reasonable, and so usually with a little compromise we can successfully guide them through the process. It is important to us that what we do looks good, whether it is a back extension, a side extension, a side extension, a front extension or a dormer window. Basically, a bit of care with the design clearly pays off.

96 percent success rate

Written by Tony Keller – Building Tectonics Ltd.

Design and access statements, what are they?

Design and access statements are documents which explain the thoughts behind the designs for a new planning application. They are submitted as well as the application which is made public for anyone to see, and so they should avoid any jargon or using very technical language. It is very important that they are written specifically  for the application which they are accompanying.

The statement should include a written description and justification of the planning application, sometimes photos, maps may need to be added as supplementary information to clearly illustrate the points made.  They don’t need to be very long, but they should be long enough that the included details reflect how complex the project is, therefore, a statement for a major development would be longer than one for a singular building.

The document itself should include a brief description of the process which brought you to the scheme which you are submitting. This should include the thinking process behind each of the following points:

  • Use – What the development will be used for.
  • Amount – How much is being built on-site.
  • Layout – How the building(s) and private space will be arranged on-site, and the relationships between those and the existing buildings around the site.
  • Scale – How big the building(s) will be (height, width and length are all included).
  • Landscaping – How open spaces will be treated to enhance and protect the character of a place.
  • Appearance – What the development will look like. (E.g. materials, detail etc.).
  • Access – The statement should include two possible aspects of entrance.
  • Transport links – Why the access points shown have been chosen.
  • Inclusive access – How everyone can get to, and move through the place equally regardless of age, disability, ethnicity or social grouping.

The rules for outline applications changed so that they must include a minimum amount of detail on:

  • What the building(s) will be used for
  • How many building(s) there will be
  • Roughly, how they will be laid out
  • Minimum and maximum building sizes
  • Where entrances to the site will be.

They should also include some information about how having the development can create accessible and safe environments, including addressing crime and disorder and fear of crime. They can include more information than the brief description given here, if the applicant believes that the extra information is also relevant.

In short, statements accompany an application but they’re not apart of it, they should explain and justify what is being applied for and this statement should set out the aims for the whole design, even if some details still need to be drawn up.

Written by Jade Turney – Building Tectonics Ltd.

Feasibility Schemes & older houses that have been altered before.

A potential new client wrote: We moved into our house a few years ago and are now looking at ways of maximizing the current structure. The original part of the house dates back to approx 1890 but it has been extended several times since. We feel there may well be a better way of utilising the current design, and may even need a small extension.

This is a problem that is pretty typical of the older house that has been altered a few, or many times before. It is exactly the type of problem we undertake to resolve. Often houses that have been altered numerous times suffer from a lack of coherence due to a poor spatial relationship or juxtaposition of the rooms. This can come about because each incremental alteration has been an attempt to satisfy a particular occupiers need but often fails to work holistically in terms of the overall house layout. Some times it is the layout that is imperfect, such as having to pass through a less pleasant space to reach a lovely lounge for instance, or perhaps the spatial balance is wrong where for example a beautiful ground floor, has been created but the full value of the house is hampered by having a small cramped upstairs.

Building Tectonics commence such a project with a what we call a Feasibility Scheme Stage.

In brief this involves me visiting the house, listening to the requirements, measuring the house and surroundings and taking the information necessary to produce workable schemes. This visit takes about 3 & 4 hours. So you can see we are pretty thorough. Following this visit and survey we produce a feasibility Scheme, or more usually, feasibility schemes, for the clients consideration, as we like to give the client as many options as possible. We normally get these schemes back to a client about 4-5 weeks after the visit. Once a client has had a chance to evaluate our schemes we like to receive the clients thoughts so we can then further explore a particular idea, altering it as necessary.

Once the client is happy with the proposals we would normally send the scheme to the Planning Department for an informal view. This is not a formal Planning Application at this point, it is an informal enquiry. On receipt of the Planning Departments comments we would try to factor in any comments they may make. It is possible that they may say that you do not require Planning Permission and it is useful to have such a letter on file for when you come to sell your house.

For a ground floor extension It would be prudent for us to carry out a so-called Asset Enquiry which means we will check whether any sewers run under your property as this may prohibit the building work you require. If we carry this enquiry out, the water authority will charge and so we have to make an additional small fee.

Once the scheme has been agreed we can then assess what further costs will be incurred in order to proceed. We can obtain an approximate build cost from a competent builder if wished. We can also obtain any structural engineering costs from a Structural Engineer, which may be required in order to move to the next stage. We are thoughtful designers and we do our best to keep our clients costs down. We often spend a little extra time producing a scheme that is more cost-effective to build. By careful analysis of the requirements a design can sometimes be produced that does not requires an Engineer. This care can also benefit the client by reducing the build cost and the disruption to the clients home – particularly important and often overlooked.

Our fee for all of the above service is usually £600.00 for local jobs but please contact us if you are interested, to see if this is still applicable.

Once this stage has concluded we can then quote you for the preparation of detailed plans for the local authority applications namely, Planning and Building Regulations. We are able to give a fixed price quotation for Planning and Building Regulation at this point because we now know what the scheme consists of. We can also advise you of other matters that you may have to be aware of such as Part Wall / 3 Metre Notices, which is sometimes needed.

If you have any queries or comments at any time, we would invite you to contact us and please remember, we have found from many years of experience, that it pays to be thorough at the outset of a project by thoroughly examining the clients requirements and seeing how the existing house can be adapted. This is why so many of our projects get built on time and on budget and with the minimum of drama on site.

Please note that Building Tectonics reserves the right to change or withdraw the above details at any time.

Written by Tony Keller – Building Tectonics Ltd.