Prefab/SIPS extension

Daddybear85

Hello me and my wife are buying our first home, but we will need to build a "granny annex" on the side for her parents to move into so we can look after them as they are struggling with poor health. my question is has anyone used a sips/prefab extension company and if so would u recommend this as a good idea?

Furts

I would never entertain a prefab or sips extension, any more than I would recommend a conservatory as a better substitute for a properly built sun room.

The good practice answer is to build properly with time proven materials and procedures.

A sips or prefabricated concept is fine if one is looking at a garden shed, or log cabin, or similar. Basically something which is temporary, or short life.

I accept that my opinion will be deemed unpopular and unfashionable. To counter this I add that it is based on decades of experience in the construction industry

ed110220

Nothing wrong with SIPs, it's likely to perform much better thermally than the main house if that's of traditional construction. Even more important if they are in poor health as it will likely be more comfortable due to the better insulation.

Ed

Furts

ed110220 wrote: »

Nothing wrong with SIPs, it's likely to perform much better thermally than the main house if that's of traditional construction. Even more important if they are in poor health as it will likely be more comfortable due to the better insulation.

Ed

OP will be making the decision and quite rightly because it is their money.

A question that should be carefully pondered over...Which is preferable in terms of solidity, thermal mass, rot and decay resistance, to name some items. Is the answer softwood shavings compressed into a board and held together with adhesive. Or is the answer bricks, blocks and mortar?

Those who answer the former should reflect on the timber frame housing scandal of the 1980s which still blights the industry. They should also reflect on the current blights of noise insulation and fire integrity.

System

Timber frame is an incredibly common form of construction the world over and it improves constantly - I have worked with both for years, if you are having problems with "solidity", thermal mass, rot and decay resistance I would suggest you update your knowledge of the workings of timber frame/sips/clt construction - the product isn't the issue at all

Furts

the_r_sole wrote: »

Timber frame is an incredibly common form of construction the world over and it improves constantly - I have worked with both for years, if you are having problems with "solidity", thermal mass, rot and decay resistance I would suggest you update your knowledge of the workings of timber frame/sips/clt construction - the product isn't the issue at all

I said that my opinion would not be well received. I will avoid naming names, but numerous colleagues working with Social Housing providers have moved away from enthusiasm for timber construction. There are contracts to be honoured, there are factories to be kept in production, so timber continues.

I have worked on, and with, numerous defective timber housing schemes. But nothing in this world is perfect, that I accept. The problems with these schemes was the mindset that CAD always gets it right, and that factory built housing will be fault free.

There are numerous extensions attached to my home. I had a free choice on how to construct any of them. None were built in timber. Equally I would advise all consumers to question all timber building systems.

The ultimate decision lies with OP

DRP

Furts wrote: »

OP will be making the decision and quite rightly because it is their money.

A question that should be carefully pondered over...Which is preferable in terms of solidity, thermal mass, rot and decay resistance, to name some items. Is the answer softwood shavings compressed into a board and held together with adhesive. Or is the answer bricks, blocks and mortar?

Those who answer the former should reflect on the timber frame housing scandal of the 1980s which still blights the industry. They should also reflect on the current blights of noise insulation and fire integrity.

what was this timber housing scandal?

Furts

DRP wrote: »

what was this timber housing scandal?

Basically an undercover TV investigation by World In Action. It crucified Barratts and sent them bankrupt or near bankrupt IIRR. It also crucified the entire timber frame industry in the UK. The industry took decades to recover and this is still a topic all in the industry would like swept under the carpet. The programme was valid. The issues raised still persist.

ed110220

But timber frame and SIPs are about as different as chalk and cheese, even if we accept timber frame is to be avoided (which is another matter). They have nothing really in common so it would be wrong to lump them together just because they're not masonry. Bit like deciding Marbella is an equally bad holiday choice as Mogadishu just because neither is in the UK.

The OP may find answers from people with more experience of SIPs on a more specialist forum such as http://www.greenbuildingforum.co.uk/newforum/

Ed

muckybutt

We had a timber frame granny annex built last year, via a local trusted builder we used Fleming Homes for the kit, Fleming were very good to deal with as was our builder.

In all it took 7 weeks to erect and make water tight and do all the fit out, sadly though my mum in law never got to see it as she passed away the week they started

System

Timber frame has advanced since the 80s!!
SIP's have some advantages over traditional construction and timber frame - any method of construction can be detailed and built well or badly - if you understand the limitations and opportunities each present it makes the selection easier but ruling out any construction method because of a 30+ year old "scandal" seems a bit ott...
Incidentally when I worked in Canada we were doing 5 storey developments in timber frame without issue.
Op, when I've used SIP's in the past its always been with a decent set of drawings rather than letting a company dictate the design... If you want any details of the companies I've used I can send them by pm