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The choice of construction has always been an issue large in the mind of all self builders and has been a subject of debate in the industry, comparing the relative merits of traditional and timber frame construction. It has also received considerable coverage in the general media; both press and TV, making the method of construction an issue for those buying ready built also. I felt a knowledgeable overview of traditional construction would be welcomed by those about to decide on a new home. Lets look at why traditional masonry construction has endured the test of time and try to identify why it is the prime method of construction for your new home. Traditional construction as we know it didn't really become the first choice for building until the Great Fire of London, up until which stone or clay bricks were used as an in-fill to oak frames. The oak frame was substantial and could be trusted to keep the weather at bay provided the spaces between were similarly weather resistant. This method worked well enough, with artisan labour erecting all manner of buildings but to standards which are unacceptable today. That was until the Great Fire revealed the system's fundamental weakness - it burned. Good for eradicating the plague, but bad for buildings! Thermally efficient
Long lead times If you have spoken to a timber frame salesman you will no doubt have been advised that it is quicker to build by this method than if you adopt a cavity wall construction. There is an element of truth in this, but it is by no means the whole story. The time to order your timber frame is when you have your planning approval, only a fool would do so before this. You will then be quoted a delivery date by the timber frame manufacturers of between 8 and 10 weeks, sometimes even longer, leaving you to prepare the footings, a job that only takes a few days. The chances are the well-organised self-builder is left waiting weeks for the frame.
A further point to remember with timber frame is that the footings must be built accurately to fit the factory built frame, if they are not then the panels may need some fairly major alterations. Again the masonry built home is at an advantage because of the flexibility inherent in the build method, allowing problems to be worked around. If time scale is important to you but you still want all the advantages of cavity wall construction you can consider large format blocks. Briefly, these are high quality, autoclaved and aerated concrete blocks that are significantly bigger than a standard block. It is possible to halve the build time for these compared to a normal block, making the construction of the cavity wall significantly quicker. The other good news is that you can still have solid floors as the walls can be designed to support them. Build costs
But to find the real facts on the different build methods don't rely on salesmen undertake your own research from independent sources. Cash flow Unless you have recently won the National Lottery it is unlikely that you have a pot of money to see you into your new home without considering finance. Stage payments to builders can also be a headache, arriving late from your lender after you have spent the money. Since package companies and manufacturers don't provide overdraft facilities you have to look at the build route to mitigate this problem. Don't blame the timber frame companies for charging so much money up front, they have cash flow problems too. The most cost effective way is to drip feed the builder with materials, not only because this involves you in less expense as you build but it also means there are fewer costly materials left on site for the thief. Masonry construction is a perfect way to build in this respect. You are more able to limit expenditure during the project and heavy blocks and bricks are just not worth stealing in significant numbers. Just be sure you don't run out of materials unless you want to pay your builders for standing time. No creaks or echoes A traditional cavity wall house with solid floors and walls throughout has that quality that is so difficult to define. It simply feels solid, secure and permanent. I suspect it is about the factors mentioned earlier making the whole greater than in its parts. It is about the absence of echo when you tap the walls, or creaks when you walk over the floors, or the sounds from other rooms and even the warmth despite the heating being switched off hours before. These are sensory factors you tend not to keep at the front of your mind but do add up to comfort. Worse still, creaks, conversations and chill air can indeed force themselves into your conscious thought and that becomes an annoyance. Timber frame forced to meet legislation It is no surprise that the ever improving standards of legislation are catching up with the values enjoyed by our clients who appreciate the merits of modern brick and block construction. The NHBC have reported a significant number of complaints in the past from customers who have found the lack of sound insulation between rooms unacceptable. From 2003 Part E of the Building Regulations included more demanding standards of sound insulation within every home built. The focus is on partitions and floors between bedrooms and other habitable rooms, between bedrooms and bathrooms as well as between bedrooms themselves. As ever, higher standards means higher costs. Not so for our clients, they have enjoyed levels of acoustic insulation comfortably meeting the new standards for years. Timber frame construction, on the other hand will require expensive modifications. Partitions will need to be lined with TWO layers of plasterboard on each side as well as the inclusion of mineral wool quilt between the studs. Whether this eliminates that unwelcome noise when you tap a timber partition remains to be seen. As far as timber floors are concerned mineral wool quilt will once again be called for. However, I can't help wondering how effective these measures will be. As always the quality of workmanship is crucial to the success of a timber frame and the mineral wool will have to be carefully packed into the partitions and floors to avoid gaps. These measures will certainly increase the cost differential between timber frame and modern masonry construction, so why pay more for less. Solid brick and block construction
Let's all put an out of date notion to bed once and for all and embrace modern masonry construction in the new millennium. For further information on modern masonry construction contact the Traditional Housing Bureau on 01344 725 757. It would be easy to conclude that there is no realistic alternative to modern masonry. In the vast number of cases I believe this to be true but SIPS (structurally insulated panel system) for external walls and roofs can have a place in a self-build project. If high levels of insulation and a genuine speed of erection are important to you then this building system may be for you. In order to get the benefits (especially the high levels of insulation) you need to dig deep into you pockets. Our research tells us that 142mm SIPS external wall panels generally add 7% to the build costs and 3% -7% for roof panels. To achieve a significant 'U' value improvement over modern masonry however the wall panel thickness has to increase to 190mm. This is likely to add 8% to 10% in terms of build cost. Given that energy costs will continue to rise you may feel this investment in insulation, along with other Eco features may be worth every penny for a sound night's sleep. For more information on SIPS go to BUILD SYSTEMS on the top menu or click here. About U value: A U value is a measurement of the rate at which heat passes through an element of a building expressed as watts per metre squared per degree centigrade. For example from the outside brick to the inside face of the plaster in a cavity wall. The lower the U value figure the better.
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We asked our Company Architect, Tom Somerville to look at the reasons why so many
individuals still prefer a solid structure. Tom holds a first class honours degree in Architecture and has been involved in
self build for 20 years. He has carried out post graduate studies on both masonry and
timber framed construction. Tom used timber frame on his first self build and opted
for brick and block on his second house.
We provide a minimum 'U' value for external walls of 0.18 w/mē/°C. All windows we supply are factory
double-glazed and the air space is filled with Argon gas to further limit heat loss.
On the other hand, the masonry built home can carry on, giving it a head start. Any advantage
that timber frame offers in speed of construction is generally lost, and both build methods tend
to finish in about the same time.
As Design & Materials company architect, it is important for me to understand the relative build
costs between cavity wall construction and other popular methods, especially in the context of
the particular needs and skills of each of my clients. Since I have built my last two homes in
timber frame and cavity wall respectively, I believe my judgement to be reasonably accurate and
unbiased. I have found cavity wall construction, compared like for like, to be cheaper than timber
frame.
I have spoken about the place of traditional cavity construction in today's housing industry
but I have to conclude that it is time to change its name to modern masonry construction.
The benefits of extremely high levels of thermal insulation and sound absorption and overall
flexibility in particular make it a strong choice for any home, meeting as it does the demands
of modern life where energy conservation and privacy are important to us all.