If you are thinking of SIPS for your build

[Bigdeadbadger]

Please drop me a message and I can share my first hand experience of a 6+ figure install and the potential outcomes.

 

whilst in principle, the design methodology has a lot in its favour, so much is dependent on the SIPS company and the install team (noting that these likely are not the same and more likely some subco’s to some subco’s).

 

It is completely fair to say, the vision you are sold - either from Architects or the SIPS company - is not guaranteed to be the reality you will see.

The concept of an airtight fabric with limited cold bridging is not a given, and unless you are abundantly aware of those limitations, there is the distinct risk that you may have the wool pulled over your eyes. 

 

 

[nod]

Not much good as a private message 

Share it on the forum 

[Bigdeadbadger]

30 minutes ago, nod said:

Not much good as a private message 

Share it on the forum 

So ask away @nod - what would you like to know?

Edited October 27 by Bigdeadbadger

[G and J]

I put a lot of time into scoping and pricing SIPs construction vs open panel (both on site and panelised). The theoretical u value vs wall thickness is attractive, though not when cost is factored in. 
 

For our modest 150m2 build diy SIPs cost at least £20k more than open panel builds.  But the hype power is huge.  The worst cases SIPs added at least £65k and the sales pressure was enormous.  
 

So, @Bigdeadbadger, share for all to balance the playing field a bit.  Think of it as a public service. 
 

 

[nod]

7 hours ago, Bigdeadbadger said:

So ask away @nod - what would you like to know?

Just share your I guessing bad experience You can leave company names blank 

[MR10]

A few questions..

1. What was the vision you were sold and what was the reality?

2. At what stage did the communication breakdown (if any)  and other fault lines appear and were there with the supplier, installer or both?

3. What were the gaps in your knowledge and what would you do differently again, knowing now what you didn't know before.

 

[Andehh]

Good questions MR10, would be useful to post pictures of issues as well, for others to consider!

[Alan Ambrose]

Yeah, unless you're slagging off Dyson or someone who does SLAPP orders, you're pretty safe if you're just reporting facts. Even better if you have evidence, like photos. Just don't communicate anything that you wouldn't want read out in court or reported in the press (which is my own guideline for anything I say publically anyway). I appreciate some people's reluctance to be transparent, but otherwise this thread is a bit of a tease without any content.

 

And if you don't tell us (a) some of us are going to fall into exactly the same trap, which we would prefer not to, and (b) the organisation in question has every incentive to carry on carrying on.

[Kelvin]

I’ve been open about the issues with our timber kit on here albeit not a SIP kit. 

[Bigdeadbadger]

The goal of this thread is to try and share topics for people to consider both in terms of their SIPS company and the SIPS system.  I have tried to keep emotions out and try to structure the information so that it reads OK.  However I'm sure some parts may appear random.  

 

Your mileage may vary and not all SIPS companies, and SIPS systems are the same. Likewise some of these situations could equally apply to non SIPS builds and just be good practice, however I would encourage the following:

 

For many self builders, this will be their first time building a home (myself included) and therefore having the right things to look out for can be pretty useful.

 

For context, my build was less modest than @G and J at over 300m2.

 

1) Understand how their contract is structured (and why).  This is not the SIPS companies' first rodeo.

 

Your SIPS company may want to sign you up for ‘Design’, ’Fabrication’ and ‘Install’. As a self builder, this can sound appealing as it means all this complexity is dealt with by one company and a single point for you the self builder to deal with. They may even offer to use their own appointed Structural Engineers as well.  In this model, there are 2 key risks to watch out for. Firstly, their goal is not necessarily to design the physical house as you want, their goal is to design a structure that meets regulations, to the lowest cost/highest margin possible to them.  So when discussions arise over compromises in the design, what you may find is that this package deal is compromised so you are the one making compromises.  The 2nd and related risk is, they will load the contract with substantial fiscal penalties for withdrawal - such that your leverage to walk away from a design you many not be 100% happy with is left at almost zero.  Same goes for using their Structural Engineers, as in this model, they are working for the SIPS company, not you. So their interest is in keeping their client happy - which is the SIPS company. 

 

So what can you do to avoid this?

 

Break the contract down into smaller chunks that allow you to exit if your needs are not met.  This will be a common theme in this feedback, but you need to be prepared that this will take time to negotiate and you need to be prepared that they may refuse and therefore prolong your search for a SIPS company. 

Same goes for the SE, find your own structural engineers who work for You - the paying customer. 

 

Granted, exiting at this point will still have a cost, but it is far far smaller than the potential penalties over the whole package value.

 

2) Design compromises, Steel and Timber vs SIPS public image

 

In my experience, the value proposition of SIPS for large open spans and vaulted ceilings - especially on our 2nd floor did not reflect reality. What we ended up with was effectively a steel structure holding up SIPS panels. This was with even modest room widths (4.5m) and a 35degree pitch roof. (I will

come back to steel later in the install topics).  This room has both a Steel ridge and 2xSteel rafters, and its overall floor area is 20m2, so not particularly big.

 

These steel components - more so the rafters, represent lovely cold bridges down through your SIPS envelope.

 

In addition to this, what you may see in the pictures relating to joining your SIPS panels is the SIPS splines. In reality, what you may see is the splines replaced with timber. Again, some of this will be by engineering need, however in my case I have more timber than splines. Especially on my roof. This giving me in many places an effective width of 4 joists between SIPS panels (timber spline:rafter:rafter:timber spline). So again, rather than a complete SIPS envelop, you are left with more lovely cold bridges which will need more insulation (internal layer of PIR) to compensate, even with the thickest of SIPS panels - thus defeating a huge point of why you may have selected SIPS in the first place. 

How to avoid this? Again this goes back to contracts and breaking out at least the design phase as a single entity. That way you have a chance to force more of these topics and leverage to walk away. 

 

Ask for examples of final fabrication designs that are similar to yours (in terms of scale/size) BEFORE signing up.  The final fabrication is important, as this is where the rubber hits the road and you can see how they intent to fabricate the kit. 

 

3) Installation

 

What you may find is your SIPS installers have no affiliation with your SIPS company and there may be several layers of subcontractors used, potentially ones that have never installed SIPS or worked for your SIPS Company before.  In my experience, my SIPS company were an abject failure in managing the install team.  Those failures were not limited to:  No formal project planning of the install, around when installers would (or would not be) on site, what sequence of install events needed to happen in what order, how installers were paid, how long the install would take and large gaps between reviewing install accuracy and completeness. 

 

The net effect of this is that it is YOU that is left to manage the install team, and subsequent impacts and fall outs from install issues.  

 

4) Scaffolding (and other ancillary dependencies like plant)

 

Your SIPS Install team will need scaffolding to complete the install.  Demand a scaffolding plan from the SIPS company a minimum of 6 weeks before install is due to start.  That plan at minimum should cover the number of lifts, any initial gaps for access, at what stage in the build additional lifts may be needed.  Going back to point 3) my experience was that the first time the install team looked at my design and any complexity was 1 week prior to arrival, where a long list of pre-requisite expectations were then given - over and above the pre-flight install checks I had already completed with the SIPS company.  This is because in my experience, the SIPS company basically scoured the UK to find "anyone" who might be available to install a SIPS kit (more on this coming).   

 

The net effect of this is delays to your program - I had to get scaffolding basically at a weeks notice which then puts the pressure back on you and compromises how thorough you can be in securing those services.

 

Furthermore, once install commences, demand ongoing updated scaffolding plans to reflect any changes they might need in advance (with a minimum 1 weeks notice).  In my experience, my installers planned only from one day to the next.  Meaning they could ask for scaffolding changes almost every other day.  This requires you to then get your scaffolding company on a hotline - and costs a ton of money.

 

As I'm sure applies to many of us, our designs are not square boxes, again, part of the value prop for SIPS was for creating interesting shapes, roof overhangs etc, all of which make scaffolding more complex than a square box new build from a major house builder.  So there is an understanding that modifications in the scaffolding will be needed.  However these cannot be managed on a day to day basis. 

 

5) Timelines - Plant machinery

 

Demand from the SIPS company a contractual timeline for the install.  This needs to be done at the beginning of the engagement with your SIPS company.  They wont like this, because it forces them to think and try and evaluate risk early on in their work and have methods to hold their subcontracting installers to account, which they are not used to doing.  The numbers they generally provide are based on an average build and where everything has run smoothly.  DO NOT assume this will be the case.  It was not for me, and I know not for others as well.  Any notion of a 4 week build for the kit is not realistic.  Something large and complex may be something like 16 weeks of install time.

 

This timing and planning directly relates to plant and machine hire (although I acknowledge there are other knock on impacts for when follow on trades can start and your overall build plan).  DO NOT assume the responsibility for plant hire (cranes and telehandlers), push this back onto the SIPS company.  Why? because when it's on you, you will be amazed how little bother is given to how efficiently this plant is used, whether it's busy or idle.  Likewise when someone else is paying, the need to be specific in what is required is replaced by asks for the biggest (and therefore most expensive) equipment that takes any challenge off the install team.  And of course, if the install takes longer, its you picking up the tab. 

 

Part of this experience is based on hearing about installers who more frequently work on building sites, where multiple houses are being erected, at different stages.  Meaning they can hop between installs as they wait for something, or some dependency to be cleared.  So on those builds, the equipment always looks busy as it's serving multiple builds and a) they don't give it a second thought to the use of the plant and b) they always expect it to be there waiting on them on tap.  This is obviously not the case on a single self build (i.e. most of us). 

 

6) Installer competencies

 

Following on from my earlier comments around the volume of steel in my build.  My installers had limited experience of installing steel at this complexity or volume (~70 individual steel pieces).  I would have been bettered served with a dedicated steel install team.  Why? My install team could not set out where steels would be placed, and therefore worked on a model, where a steel was placed, then SIPS walls added, until they needed the next steel in place.  This stepwise fashion of steel, sips, sips, sips ... N+1 then steel meant the hired crane sat idle for most of the day(s) rather than placing as many steels into place as possible.

 

Even simple concepts like pre-erecting joined steels on the ground prior to lifting was unknown to the install team, thus meaning each steel was lifted one at a time.

 

Furthermore, this stepwise method prevented the steels from being bolted and levelled until after all panels were installed.  This leads to panels covering over the steel pads and holes for bolting, which then leads to large sections of SIPS panels needing to be removed at a later date to access these bolt holes!

 

What is most galling over this scenario (beyond the wasted crane time), is the tolerances that the SIPS company demand for your slab (+/- 10mm over 10m), yet they could not accurately place steels without this step wise build method. 

 

7) Marking their own homework

 

You may find there is no "formal" or "accredited" sign off for your installation.  That process is an internal one where your SIPS company effectively self certifies their install is in line with the approved design (you can already probably guess where this heads).  

 

As the client - you need to find other ways (either yourself or through other professionals) to mark their homework.  In my scenario (I ultimately feel lucky) I caught structural defects in the installation method BEFORE it was too late.  This is especially challenging when some build parts do go quickly and large swathes of a building go up before you might get a chance to check. 

 

Those defects resulted (painfully) in a 2 month wait for the SIPS company to acknowledge (and no progress on site), and then further install delays as they removed panels and re-installed correctly.  Roofing and Wall membranes can hide a multitude of sins.  Don't wrap the building until you are happy. 

 

8 ) Foam or no foam

 

In my re-search prior to finding a SIPS company, I had never come across the idea of a dry fit SIPS kit. This is where NO foam is used during panel install, and only used sparingly at the end of the build.

 

I came across DRY fit once my install started as that's what the SIPS company stated was their approach.  This contradicts their public documents, every other kit I looked at, and also, any notion of having a (reasonably) airtight fabric.  

 

As i was doing some adjustments at the weekend to move a location for velux, here is a great example of what happens with a timber spline into a SIPS panel without foam.  No whilst I know more of my kit is foamed than it may have been (as i caught it early), I know for a fact it is not consistently foamed with any quality. 

 

What can you do to avoid this? Get it in writing that the kit will be foamed on every join DURING install, and watch them like a hawk. 

 

 

This is probably a good place to end for the moment, needless to say, I am not a SIPS fan (for all of the above).  It has brought needless delay, complexity and above all significant cost - you could realistically buy a decent home for the amount of money it has cost for this kit and its install, without any of the upsides of speed or thermal performance.

 

I'm fully aware my experience is a sample size of 1 (with some other bits of feedback I've gathered directly) - however it is real world experience.

 

 

 

Edited October 28 by Bigdeadbadger

[Kelvin]

It wasn’t Heb Homes was it? 😂 I had a similar experience. 

[Alan Ambrose]

Oooof, that sounds a complete nightmare. Maybe SIPS is the new double glazing?

[FuerteStu]

I've never worked with SIPS but I can imagine there are all the variables of timber frame. But with all the mistakes and snags already covered up. 

 

As with all construction, 90% of the finish product is from the quality of the tradesman involved. It's not something you can afford to wait and find out how good they are, you need to see their work beforehand, and speak to their previous clients

 

 

[saveasteading]

I've noticed that all timber kit people, sips or stick, exclude steel and scaffolding.   As if they have no idea what will be needed. 

Thus the prices are falsely low.