Tag: advantages of timber homes

This is an excerpt from a presentation delivered at the HWZ Third Wood Conference, 8 Feb 2013, CTICC, CapeTown

STATISTICS

Despite statistics such as 70% of the developed world’s population live in timber frame homes, and despite the resurgance in the popularity of timber homes in Europe in the last decade, my question is … will timber homes in South Africa remain with such a relatively miniscule share of the local market?

Numbers of timber homes built in SA were hard to find – the Local Authorities don’t collect data on the type of structure when plans are submitted; untill I remembered that one of the 2011 Census questions were: what type of material are the walls you house made of?  …and the census data is freely available.

According to the census, homes of a current value of R1m and upwards, which are not ‘bricks or cement block / concrete’, account for less than 0.38% of the total, with the figure for new houses built from 2000 to 2010 at just over 0.5%

TIMBER HOMES IN SA – A brief history up until now

The predecessor of the timber home in South Africa are the wood frame and iron clad homes, some imported in kit form from Europe, and others designed and built here – in the late 1800’s to early 1900’s. The most well known of these is the Smuts House, pre-fabricated in the UK and shipped to India, and later brought to South Africa where it was re-erected at Doornkloof for Jan Smuts in 1909.

An example of an iron clad timber frame building designed and built locally, is the Globe Tavern in Barbeton, which opened for business in 1887, designed by Arthur Hubert Halder.

Another example is the Millwood House, now a museum in Knysna. The house was originally built in Millwood during the ‘Gold Rush’ (very little Gold was found) in 1885, and was later relocated to Knysna, in sections, by ox-wagon, and re-constructed where St George’s Church Hall now stands. It was moved to it’s present site in 1910.

An example of a remaining timber clad building from that era is the Woodcutter’s Cottage, built in the 1880’s, on display at the George Museum.

After that era of timber frame building, iron clad timber frame buildings fell out of favour with the local authorities, and a period followed when they were all but completely outlawed. Many of our older title deeds still have clauses like ‘no corrugated iron’

Up to the 1950’s, the few timber buildings that were built were still being built of hardwoods. It was only around that time, with the introduction of preservative treatments, that softwoods such as Pine started gaining in popularity as a construction material, and was in the 1960’s that timber buildings were re-introduced as an alternative to brick and mortar.

Among the pioneers of this re-introduction of timber homes were Searles Homes in Great Brak River, who initially built timber frame homes to house the staff for their shoe factory. Others were Elgin Homes in Grabouw, and NST in Knysna, who introduced solid wood and log cabin building systems.

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While it’s evident that much of the design at the time was based on practicalities, an exception to this was the magnificent Bruynzeel House in Stellenbosch, with its hyperbolic paraboliod roof, designed in 1960 by Aart Bijl and built by Kees Bruynzeel, a Dutch wood merchant.

The majority of timber homes at the time, however, were relatively inexpensive holiday homes built along the Southern Cape coast, many of which were prefabricated.

In 1982, some members of the timber building industry got together to form the Timber Frame Builders Association, now called the Institute for Timber Frame Builders, which went a long way in achieving the recognition the quality timber buildings enjoy today, particularly with regards local authorities and lending institutions.

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If we look at a graph from the 2011 Census data showing the percentage of ‘non-brick & cement block’ houses since 1960, we see, however, that beyond the spike in the 1960’s (from close to zero % before that), little if no growth in percentage has occurred up until now.

This is while the percentage of timber buildings continues to increase year after year in many parts of the world, as people become more aware of the benefits of the systems available.

I can only guess that the perception of timber homes as a cheaper & less desirable alternative, perhaps still a result of it’s humble iron clad origins and later cost–effective prefab holiday house, still persist amongst many.

WHY TIMBER HOMES?

What is the fuss all about? Should we not just continue doing things here as we allways have, building most buildings out of bricks and mortar? What are the benefits?

For the Client: 

  1. Insulation – and therefore energy costs. Perhaps not yet such a huge issue, but with a potential electricity hike of around 16% for the next 5 years at this stage, it soon will be
  2. Natural Home – many clients chhose to build a timber home because they want a more natural home, that better fits into it’s environment. The same applies to beach resorts, and lodges in nature reserves
  3. Ease of construction and time to construct – it takes significantly less time to build a timber home than a similar brick & mortar home. It’s also easier to alter or add on to at a later stage – and a lot less messy.
  4. Difficult & Sensitive sites –  due to using relatively lightweight materials, several of my projects have been on difficult to access sites – where getting timber there is pretty easy compared to bricks. For sensitive sites timber construction also allows one to nestle right in between the existing vegetation with minimum disturbance. There are also cost savings on steeps sites, by using suspended floor structures

For the Environment: 

  1. Less energy used = less emissions  –  untill such time as our energy is produced from renewable resources, and not coal, any savings in energy are savings in harmfull emissions
  2. Low embodied energy – Of the various readily available raw materials for building, timber has by far the lowest embodied energy, and if grown in a sustainably managed plantation, is a truly renewable building resource. In terms of strength to weight, radiata pine, for example, has a strength to weight ratio 20 percent higher than structural steel, and more than four times that of unreinforced concrete in compression.
  3. Carbon sequestration – Trees absorb carbon as they grow and this carbon is locked away when the timber is used for construction – so the more timber you use instead of more energy and carbon costly materials such as masonry and concrete, the lower the carbon footprint of your home
  4. Treatment – most preservative treatments, which while providing the benefit prelonging the lifespan of timber indefinitely, have not been considered ideal from an enviromental perspective. This is changing with the introduction of new preservative treatments such as Tan E, which was recently accepted by Ecospecifier global

For the Architect / designer:

  1. Contemporary  – driven by technology everything around us is advancing in leaps and bounds. Think cellphones, tablets cars. Timber, along with other new lightweight building systems, allows us to be part of that technological revolution – rather than still building the way we were in the pre digital age. Technological advances in design software and digital fabrication technologies are now to allowing timber to be cut and fashioned to any shape you desire.
  2. Versatility – So thanks to the extreme versatility of timber, your timber home could be anything from a humble log cabin, to a grand Cape Cod style beach house, a sleek glazed all round clad post & beam house, or a digitally crafted open plan contemporary house with a freeform double curved roof.
  3. Building Regulations – Timber homes are included in the South African National Building Regulations standards, in SANS 10082, Timber Buildings. When built to these standards they also automatically achieve the standard required for registration with the National Home Builder Registration Council (NHBRC). They are also easily designed to meet the requirements of the new Energy Efficiency regulations SANS 10400 Part XA.

For the Builder:

  1. Passion – speak to any specialist timber builder and you are likely to find someone with a passion for their craft and for working with wood. Who would you rather have building your house?
  2. Precision & neatness– building with timber is a precise form of construction. Everything needs to be just right to work. For a builder and all involved it’s easier to monitor and see that everything is working according to plan. 

TIMBER BUILDING POLL with TIMBER IQ Magazine

In trying to understand, given the clear advantages and consistently small uptake, I recently set up a poll, along with Timber IQ Magazine, to help determine the attitudes towards timber homes in SA.

We had just short of 120 respondents, of which 29% were in the design or architecture field. What was most interesting was that 38% of the respondents had previously or currently still, live in a timber home.- and clearly wanted to share the advantages. And though I had not anticipated that such a large percentage of respondents would have lived in timber homes, their responses were of the most interest – particularly, because in each of the following cases, their responses, on average, rated higher than those who had not lived in a timber home

When asked to rate timber homes compared to brick, where an answer of 1 is much less, and a 5 far superior, in favor of timber, the average scores were as follows:

– Energy Efficiency                                     3.93    (3.80)

– the time it takes to build                           4.60    (4.41)

– maintenance requirements                        2.87    (2.70)

– Risk of fire                                               2.60    (2.35)

So, while at best the results could be said to be biased, as it was mostly people who like or have lived in timber homes who took time to do the survey, what I found relevant is that the comments by people who have lived in them showed that timber homes, even amongst this sample group, perform and are generally better than what the perception is.

CONCLUSION

So to answer the earlier question, will timber homes remain marginal in the built environment in SA? ….or will we see it grow as elsewhere?

My guess is that is that, as the pressure on resources increases, the efforts to slow down global warming escalate, energy costs escalate, along with the ever increasing technologies, there will be a shift. And possibly a large one.

And at the current low base of at best 0.5% of the market, even a 0.5% shift from brick to timber frame represents a 100% increase in demand for timber homes. And a still relatively small, compared to elsewhere, say 5% shift, represents a 1000% increase. I think the timber building industry may soon get very busy, and I invite more participants.

Many people have asked why it is that I prefer to design timber frame homes, and more specifically, what the advantages of a timber frame home are. Here are 10 good reasons to build your new house using timber frame.

 

1. Touch the Earth Lightly

The choice of a timber frame home is going to substantially lower your carbon footprint. Trees absorb carbon as they grow and this carbon is locked away when the timber is used for construction – so the more timber you use instead of more energy and carbon costly materials such as masonry and concrete, the lower the carbon footprint of your home. Timber is also a totally renewable building material. In addition, because of the relatively light weight of timber frame materials, less energy is consumed by the transport of materials.

From a purely ecological perspective, a lot less damage is done to the site immediately surrounding a building project when building with timber frame. This is because the work predominantly consists of ‘dry’ trades where products are ‘fixed’ and installed as opposed to ‘wet’ trades where products are mixed and applied on site. Meaning, quite simply, less mess.

2. Keep Cool

The structure of a timber frame wall is essentially a hollow cavity with evenly spaced structural timber studs. It is the nature of this cavity, along with the fact that the high insulating properties of timber prevent ‘thermal bridging’, that allow the wall to be easily filled with as much insulation as is required to produce a thermally efficient home – as long as it is designed correctly in terms of optimal orientation and positioning of glazing of course. The amount of insulation required for optimal efficiency, as well as to comply with the recent SANS 10400 Part XA Energy Efficiency regulations, differs depending on the climatic zone in which you are building.

3. Keep your options open

Despite it’s history as a traditional building material; as the trend towards the use of sustainable materials increases, timber is also gaining popularity with designers and architects as a material in contemporary architecture. Technological advances in design software and fabrication technologies are now starting to allow timber to be cut and fashioned to any shape you desire. So thanks to the extreme versatility of timber, your timber home could be anything from a humble log cabin, to a grand Cape Cod style beach house, a sleek glazed all round clad post & beam pad enclosable by sliding shutters, or a digitally crafted open plan contemporary house with a freeform double curved roof. The choice is yours.

4. Change is inevitable

Families get bigger and families get smaller. Children move out, older parents move in. You accumulate more stuff, occasional edit, but mostly accumulate still more stuff. Over the lifespan of a typical house countless changes occur with regards its spatial requirements. And you can be sure that this will at some stage involve building new walls, or breaking old ones down, expanding outwards or upwards or opening up.

Whatever your future change requirements, they will be easier, quicker, less intrusive, and usually a lot less messy with a timber home than attempting to make changes to a conventional brick and mortar home.

5. Less is more

The first question many people ask when enquiring as to the estimated cost of a house is ‘how much is it going to cost per square meter?’. As there are so many variables, for example finishes, proportion of windows and doors to blank walls (windows are more expensive than the equivalent area of wall), and the complexity of the design, that unless the design and finishes have been decided on, the question is not that far off the ‘how long is a piece of string’ question.

A more interesting question to consider may be, ‘how many square meters of internal floor area you getting as a proportion of building area? Did you know that, because timber frame walls are so much less bulky than brick walls, you gain approximately 1 sq.m of internal floor area for every 7 running meter of external wall length? The maths is like this; typical cavity brick wall at 300mm (including plaster) less typical timber frame external wall at 150mm (including lining & cladding) equals 0.15 sq.m of floor area saved per metre of wall; multiply by 7 RM and you get 1.05 sq.m.

So next time you are comparing ‘sq.m rates’, don’t forget to factor this in to your sums.

6. Time is money

Literally, when it comes to building – assuming you own or are paying to live where you do while building. If you have just sold your house in order to build a new one you will presumably be paying occupational rent. If you are wanting to sell on completion of the new build the sooner you can do this the better. Renting speaks for itself. If you are building a guesthouse or lodge the sooner you can get bums in beds the better for your positive cashflow.

Whichever way you look at it, a longer time spent building costs you more. Now consider the fact that a timber frame home typically takes half to three quarters of the time to build than a conventional brick and mortar home.

7. Rest Assured

Besides the knowledge that you are making a positive contribution to global sustainability, you can also have complete peace of mind about the sustainability of your investment. Timber frame homes are included in the South African National Building Regulations standards, in SANS 10082, Timber Buildings. When built to these standards they also automatically achieve the standard required for registration with the National Home Builder Registration Council (NHBRC). They are also easily designed to meet the requirements of the new Energy Efficiency regulations SANS 10400 Part XA.

Build using a builder who is member of the Institute of Timber Frame Builders and you will also have the backing of an organization with a 29 year tack record of promoting and maintaining acceptable standards in timber construction in South Africa.

8. Stay safe and sound

Timber is strong, light and reliable, making timber construction on site simpler and safer than concrete or steel construction. In terms of structural material, radiata pine, for example, has a strength to weight ratio 20 percent higher than structural steel, and more than four times that of unreinforced concrete in compression.

Timber is also flexible, meaning less chance of structural damage typically caused by heaving clay, or the settlement cracks typicaly found in masonry construction at  the top corners of doors and windows.

Modern timber construction also has increased fire protection due to the use of non-combustible linings protecting the frames, the availability of fire retardants, and designing for safety by using mass timber with sufficient charring rates. Safety in the case of a fire is all about safety of the occupants, and timber homes, designed correctly, meet all of the fire safety ratings and requirements.

9. Home and dry

With a correctly designed and built timber home you will never have to worry about typical brick homeowners issues such as rising damp, or for those in the Cape, moisture breaching the cavity. Furthermore, arrive home on a cold winters evening, and a cosy fireplace or heater will heat the home up in no time. This is because, due to the low thermal mass and therefore low thermal conductivity of timber frame construction, the structure itself won’t need to absorb heat to warm up before you can warm up the space.

Use timber cladding in some of your living areas and you’ll also get the additional benefit of the feeling of warmth and cosyness exuded by natural timber.

10. Deal with people who care

Why is it that there are magazines, websites, online interest groups and forums, and building awards dedicated to timber construction? Now I’m not saying that builders who don’t specialize in timber construction don’t care about their work, but you can be sure that most timber builders are passionate about working with wood and take huge pride in their craft. So if you are going to be going with the lowest bidder (which in all likelihood you are), why not ensure that at least that is a choice to get your home built by people whose work is their passion.

 

Jacques Cronje

www.timberdesign.co.za