21 Sep 2009

UK SIPS Association

Last week I made it across to Birmingham's Think Tank to take part in the launch event of the UK SIPS Association. SIPS as a building system has been around in the UK for nearly ten years and elsewhere, notably the States, for much longer. However, nowhere has it ever taken off and become mainstream and if you've wanted to build in SIPS you have had to deal with one of a small number of specialists dotted around the country.

Time for the SIPS industry to promote itself a little more effectively. The question for the SIPS boys (and they are almost all boys) was whether to tag along with the UK Timber Frame Association or to branch out on their own? It's not an easy call, because there are many similarities between the build systems and there are also hybrid walling systems around which are not easy to identify as either SIPS or Timber Frame. Google Supawall if you want to see what I'm on about. Largely at the prompting of John Tebbitt of the Construction Products Association, SIPS have decided to strike out on their own, hence this event.

Doubtless it will be the start of a long journey. SIPS doesn't have anything like a Quality mark or a generic type approval, so each individual system (and they all seem to vary a little) has to proceed down the lengthy and expensive path of 3rd party certification: not surprisingly, the BBA were there, in the shape of Alan Thomas, suggesting what a good idea this was, but I have my doubts. SIPS are inherently strong and if put together properly should be more than adequate for any low rise building, and the risks from fire and flood seems to be identical to conventional timber frame, which is no longer expected to prove itself fit for purpose because its been around so long.

Another issue facing SIPS is the perceived premium price. Just how much more expensive than blockwork or timber frame is hard to say, because its not a commodity product which can be easily costed on a spreadsheet line by line. Instead quotes are done on a supply and fix basis. It seems that SIPS are likely to be more cost effective when the roof is being utilised as living space, but to date most SIPS customers have been primarily interest in energy saving, not cost reduction.

The one company that perhaps gives the lie to this is Custom Homes who, back in 2006, started offering their houses in SIPS versions instead of conventional timber frame. As they didn't charge any extra for SIPS, their customers switched en masse to SIPS and now they do SIPS almost exclusively. That would seem to suggest that even if SIPS are more expensive, the cost differential is so small that it's meaningless. There is of course a lot of hope that code changes will make other systems comparatively more expensive and that over time SIPS may become cheaper than anything else, but that in turn may cause a whole new set of problems as big producers suddenly muscle in on the scene, pushing out the niche suppliers. But that's a worry for another day.

Bill Wachtler of the US equivalent body, SIPA, gave a 20 minute presentation on the American experience. SIPS there remain a premium product, accounting for less than 1% of the residential newbuild market and last year they completed no more than about 6,000 SIPS homes, down from 10,000 in 2007. That may sound bad, but then he showed a slide showing how US housing starts had deteriorated in general: from 1.7 million new homes in 2007 down to an estimated 450,000 this year. That's a 75% reduction. In the UK, the equivalent figure shows a mere 60% reduction. Even so, that's some downturn. It's a wonder that everyone remains so optimistic.

By the way, as a budding reporter on the SIPS scene in the UK, I can’t be the only one to be confused by the similarities of many of the names. So here, for my benefit as much as anyone elses, is a bluffer’s guide to the SIPS scene.


• Kingspan Tek System: now just a supplier of PUR SIPS from Germany, used by a number of installers (formerly process partners), notably SIPS of CLAY in the selfbuild sector

• SBS Building Systems, makes PUR panels in Widnes and supplies SIP It Scotland, SIP Build in the North and Built It Green in the South.

• SIPS UK, aka SIPTEC, is the business started by Tony Palmer in Northamptonshire but now mostly concentrating on overseas markets. SIPHouse is their current manifestation in the UK market, but they no longer manufacture here.

• SIPS Industries, formerly BPAC, is the Fife based manufacturer and installer of EPS panels, run by Charles Stewart.

• SIPS EcoPanels is the SIPS offshoot of Custom Homes (closely related, but independent from). The panels are EPS-based and made in Scotland. Contact is Peter Keogh.

• Hemsec produce PUR SIPS on Merseyside, but aren’t really in the selfbuild market. Main man is Richard Daley.

• Innovare Systems, based in Coventry, are in the social housing market mostly, and seem to be part of the Osborne Group. Main man Andrew Orriss, now chair of the UK SIPS Association.

Have I forgotten anyone? Or got something wrong? And why is it that Scotland makes EPS panels and England PUR?

5 comments:

  1. Mark,
    You say that SIPs vary 'very little.' This is not entirely true - though it is subtle I admit. Some SIPs are adhesive bonded systems - insulation glued to the OSB (or what ever substrate). As I understand it these systems have a lower racking strength. SIP systems use PUR as the insulation and the adhesive, these systems, I understand, have a better racking strength.

    I have learned that when you ask a SIP manufacturer "is a SIP system a timber frame system" they say "No" yet I have come across SIP manufactures that say "you can use either the Accredited construction details or the EST best practice details. These details are developed for timber frame systems. Whilst there are similarities SIP manufactures can not be included and excluded from a certain camp "at whim." Something suggests to me that the SIP industry needs improved QA or self understanding.

    SIP manufactures claim that they have a low timber fraction. This is a noble aspiration but my experience it is much harder to get these guys to provide robust data that proves such statements. And getting hold of thermal bridging calculations from SIP manufactures is just as hard - they are all "being assessed by XXXX" (insert assessment organisation of limited choice.)

    In the event of fire - ensure that the SIP system is adequately protected (inside and out) - if you don't structural collapse can occur as the insulation melts. Internally plasterboard and externally a cementicious board should do the job.

    VOCs are another concern according to Lawerence Berkley Labs.

    Final comment - In my view SIP systems need to have a health and safety warning printed on the OSB. Why? The OSB looks quite inoffensive but it conceals something unexpected to most householders that are more 'familiar' with timber frame - in a SIP system the OSB is structural held together by the insulation. I personally have visions about some unassuming person routing the OSB to accommodate a horizontal services route - The result is potential structural collapse. My suspicion is that this would not occur with timber frame due to the fact that the stud take the load.

    Whilst I amdit that it is "early days" for SIPs the industry needs to take the bull by the horns and address concerns such that those above.
    Mark,
    You say that SIPs vary 'very little.' This is not entirely true - though it is subtle I admit. Some SIPs are adhesive bonded systems - insulation glued to the OSB (or what ever substrate). As I understand it these systems have a lower racking strength. SIP systems use PUR as the insulation and the adhesive, these systems, I understand, have a better racking strength.

    ReplyDelete
  2. SIPS Part II

    I have learned that when you ask a SIP manufacturer "is a SIP system a timber frame system" they say "No" yet I have come across SIP manufactures that say "you can use either the Accredited construction details or the EST best practice details. These details are developed for timber frame systems. Whilst there are similarities SIP manufactures can not be included and excluded from a certain camp "at whim." Something suggests to me that the SIP industry needs improved QA or self understanding.

    SIP manufactures claim that they have a low timber fraction. This is a noble aspiration but my experience it is much harder to get these guys to provide robust data that proves such statements. And getting hold of thermal bridging calculations from SIP manufactures is just as hard - they are all "being assessed by XXXX" (insert assessment organisation of limited choice.)

    In the event of fire - ensure that the SIP system is adequately protected (inside and out) - if you don't structural collapse can occur as the insulation melts. Internally plasterboard and externally a cementicious board should do the job.

    Super low energy buildings (think PassivHaus or Code Level 6) require an additional layer of insulation to get low enough. This adds further labour and can mitigate the labour saving advantages of SIP system. SIPs manufactures need to start addressing this before performance demands surpass their capacity.

    Final comment - In my view SIP systems need to have a health and safety warning printed on the OSB. Why? The OSB looks quite inoffensive but it conceals something unexpected to most householders that are more 'familiar' with timber frame - in a SIP system the OSB is structural held together by the insulation. I personally have visions about some unassuming person routing the OSB to accommodate a horizontal services route - The result is potential structural collapse. My suspicion is that this would not occur with timber frame due to the fact that the stud take the load.

    The SIP industry needs to address the above issues and concerns before it can be taken seriously.

    ReplyDelete
  3. Mark,

    I refer to your statement in the second para of your article:

    “It's not an easy call, because there are many similarities between the build systems and there are also hybrid walling systems around which are not easy to identify as either SIPS or Timber Frame. Google Supawall if you want to see what I'm on about.”

    I do not wish to appear to be rude, but have you any knowledge of this industry or done any research in to what SIPS and Timber Frame systems actually are, how they are detailed, manufactured and then constructed on site? By the comments you have made it would appear not.

    Example – Your link to the Supawall web site (to which you were suggesting people go) where you will find the very first line of copy on the very first page of the web site quite clearly states:

    “SupaWall® is a patented high performance closed panel timber frame building system that is one of the most advanced timber frame systems in the world.”

    I would say that this statement makes it pretty clear that Supawall is a timber frame system. No dubiety, as clear as the nose on your face, so why do you feel it necessary to add confusion where none exists?

    And to close, your statement as follows is frankly utter nonsense:

    “SIPS are inherently strong and if put together properly should be more than adequate for any low rise building, and the risks from fire and flood seems to be identical to conventional timber frame, which is no longer expected to prove itself fit for purpose because its been around so long.”

    ReplyDelete
  4. Problems with SIPS-bear in mind if you have a problem with a SIPS building, and your contractor lets you down, it is much more difficult to get anyone else to correct the problems and complete the job-this is happening to me at present, and it is not a simple case of get in some joiners to complete the work, when you have spanning panels with joints, joints in edge reinforcing timbers, missing glue, foam and nails, and timber beams installed in 3 parts. A timber framed building would be far simpler, as roof components and spans etc would be readily understood by many. This was meant to be an eco-quick erect roof, and has been on site 3 months so far. It is not easy making trips to Milngavie every time you want to contact the contractor, and he almost always fails to respond to other forms of contact, and breaks every promise made to even complete deliveries of materials paid for in April.
    The UK manufacturer of the PUR panels refuses to have anything to do with the problems of his Scottish 'Partner', and will not answer any requests for information on decay and delamination of panels already on site.
    Kenny Birch keb@rsp.net

    ReplyDelete
    Replies
    1. I am having a similar problem with my company, do you mind me asking how you resolved the matter?
      julie blake

      Delete