Truly DIY SIP construction…

[G and J]

I’m struggling re the sourcing of a SIPs solution I can be confident in.

 

I went to the Self Build show at the NEC.  Lots of hard sell, ‘give us your plans and all your problems are over’, only they aren’t, as our site access doesn’t allow lifting kit and the amounts quoted were project killing.

 

So I continued to investigate other options, and as I did DIY SIPs were suggested.  I look at the specs and it does look like a SIP based build would yield walls of the thickness I want, with better u values and condensation handling than I can achieve through traditional stick built.  Maybe with better acoustic and airtightness too.

 

So I follow a link to a blank panel provider and then engage with them and share my plans and I get back a quote for a factory made total kit for me to assemble that’s a lot lower cost than the companies at the show, but it still leaves me scratching my head.   It appears they don’t really sell blank panels any more.  

 

If I try and add up a list of the components it comes to an awful lot less than half the cost of the quote.  When I ask questions like ‘what size of posi joist have you assumed’ the answer is ‘oh don’t worry we will sort that later’, which doesn’t work for me.   I want to understand the nuts and bolts before we commit large sums, and being told not to worry, it’ll be ok is a bright red rag to an anxious bull.

 

So, does anyone know of a company that will happily sell (and therefore share a price list of) blank SIP panels and associated stuff that I can buy which would allow me to build it on-site myself?  Ideally I think I’ll need hybrid panels (i.e. ones with one skin being in anti-fire stuff as we are building less than a metre from our boundary).

[SteamyTea]

If you can build a large enough, temporary, shed on the plot, and get power to it, why not build your own panels.

A large bench and a couple of RSJ to make a jig from is about all you need to get started.

[saveasteading]

20 minutes ago, SteamyTea said:

why not build your own panels.

At a guess this will be half the cost, even if you charge in your time.

 

30 minutes ago, G and J said:

one skin being in anti-fire stuff

That is really easy too. 

 

This is basically it, gets more complex with very big rooms, but we are here for you:

https://www.instagram.com/reel/C61eu9gKm3d/?igsh=MWZwdWthZWVpZXpvYQ==

 

Edited June 4 by saveasteading
added link

[G and J]

50 minutes ago, saveasteading said:

This is basically it, gets more complex with very big rooms, but we are here for you:

https://www.instagram.com/reel/C61eu9gKm3d/?igsh=MWZwdWthZWVpZXpvYQ==

 

I guess I want to see just such a video but with SIPs being put up the windows cut out, etc.

[MR10]

12 hours ago, G and J said:

I’m struggling re the sourcing of a SIPs solution I can be confident in.

 

I went to the Self Build show at the NEC.  Lots of hard sell, ‘give us your plans and all your problems are over’, only they aren’t, as our site access doesn’t allow lifting kit and the amounts quoted were project killing.

 

does anyone know of a company that will happily sell (and therefore share a price list of) blank SIP panels and associated stuff that I can buy which would allow me to build it on-site myself? 

Somewhere like this? 

https://www.sipsdirect.co.uk/product-category/blank-panels/

[Alan Ambrose]

Would a telehandler solve your lifting problem? Also, I believe that DNOs (UKPN?) will put up temporary protection to guard against a risk building near/under an overhead line.

[G and J]

9 hours ago, Alan Ambrose said:

Would a telehandler solve your lifting problem? Also, I believe that DNOs (UKPN?) will put up temporary protection to guard against a risk building near/under an overhead line.

They will shroud next door’s overhead electric feed to prevent electric shocks but the feed itself remains vulnerable.  We can also legally apply to close our narrow road while we build but we’ll be inconveniencing the peeps who we want to be happy neighbours with for years, so we’re seeking alternatives. 
 

In truth the simple cost of a company turning up and assembling a preformed house is looking ludicrously higher than other alternatives.  When I went to the NEC self build show I saw the marketing spend and it alerted me to the profit margins that awaited the unwary. 
 

I’ve now got a good handle of the broad cost on site stick built and it’s a reasonable option.  But my gut feel is a build with sip blanks might improve on that. So my investigations continue. 
 

And as for a telehandler,we might just be using simple muscle to pop trusses onto our roof.  Just like we did in ‘91. I’m a retro sort of guy. 😉 

[SteamyTea]

4 hours ago, G and J said:

I’m a retro sort of guy

Just noticed in your in Suffolk.

Plenty of 'retro' practices next door in Norfolk, should be able to import some cheap labour from there.

[Post and beam]

3 hours ago, SteamyTea said:

should be able to import some cheap labour from there.

Likely to all look the same as well

[Post and beam]

I dont know what you do for a living but presumably while you are hand building these SIP's panels you are not earning.  The speed of a SIP's ( ready made) build has cost benefits that will affect different situations to a more or less degree. 

I am biased because i am planning a Potton SIP's build. I wonder what kind of figures you expect to save by this DIY approach.

[saveasteading]

2 hours ago, Post and beam said:

presumably while you are hand building these SIP's panels you are not earning.  

A joiner can make them on site. All parts can be walked in and the crane issues dispensed with.

2 hours ago, Post and beam said:

what kind of figures you expect to save by this DIY approach.

Yout point about earnings is valid, as is the effect of a career break.

However, I can see total diy saving being about 60 %. And income tax free.  Employing joiners, 30%. The bonuses of saving on access and hoisting will be site specific.

 

On difficult access sites I have tended (commercially, not self build) to use beam and block flooring for the same reason.

[Russell griffiths]

I have never seen a site with such bad access as @Patrick, he built on site using I joist and filled with blown in insulation. 
maybe he could share some pics. 

[G and J]

Goodness I’m hopeless at explaining things.  
 

By truly diy I didn’t mean making the SIPs myself, I mean getting a load of SIP blanks delivered to site from which I build our house.   The quote I received for SIP delivered and erected as appears standard was game over level, so I then got a kit that I assemble on site (muscle being the only lifting gear). 
 

I then ran the numbers for me building with SIP blanks and it’s starting to look remarkably good.  Problem is, they don’t sell SIP blanks at TP or any other BMs…..
 

11 hours ago, Post and beam said:

I dont know what you do for a living but presumably while you are hand building these SIP's panels you are not earning.  The speed of a SIP's ( ready made) build has cost benefits that will affect different situations to a more or less degree. 

I am biased because i am planning a Potton SIP's build. I wonder what kind of figures you expect to save by this DIY approach.

Do for a living?   Don’t be daft, I’m a bum.  (That’s an impolite term for a wrinkly.    ;-  )

 

9 hours ago, saveasteading said:

On difficult access sites I have tended (commercially, not self build) to use beam and block flooring for the same reason.

I like b&b floors but I don’t like air bricks in wood cladding.

 

 

[SteamyTea]

1 hour ago, G and J said:

Problem is, they don’t sell SIP blanks at TP or any other BMs…..

They do, usually has Celotex written on it.

 

I know a surfboard manufacturer than buys in sheet PU from Mexico.

 

The two UK towns that used to be the foam moulding places were High Wycombe and Glossop.

But it is a while since I was in the industry.

[saveasteading]

5 hours ago, G and J said:

 I didn’t mean making the SIPs myself

 But we did. It's some stud and osb with pir in the core. Standard material, no markup or transport or craning. No waste. Why not?

[G and J]

A while ago I posted seeking thoughts on what was, and was not, likely to be a good idea for me to take on myself. I’m retired but still time poor and I want our build to not take forever and cost an ok amount, and have a warranty.
 

Perhaps I’m being nervous but making my own sips would feel dangerous unless I used timber splines everywhere, in which case I’m back to being stick built.  Goodness there are so many factors!

[SteamyTea]

5 hours ago, G and J said:

and have a warranty

I am not sure, but if each component has a certificate/documentation i.e. the correct C for timber, the correct number for OSB, proper adhesives etc, then will the sum of the parts be, in effect, be your warranty?

 

[Russell griffiths]

Why not icf, very diy friendly, build it on your own apart from pour day. 
only block the road on pour day for 4-5 hours. 

 

or as I said previously I joist stick built and pumped in insulation. 
 

as far as I’m aware using sips you will need to add further insulation somewhere either external or internal, there’s many ways to do this, don’t get stuck on one method without exploring the others. 

[G and J]

1 hour ago, Russell griffiths said:

Why not icf, very diy friendly, build it on your own apart from pour day. 
only block the road on pour day for 4-5 hours. 

 

or as I said previously I joist stick built and pumped in insulation. 
 

as far as I’m aware using sips you will need to add further insulation somewhere either external or internal, there’s many ways to do this, don’t get stuck on one method without exploring the others. 

I’ve not spoken with an ICF company or a concrete delivery company but the fact that the boom would have to arch over electric cables would be a worry.  My target is a total wall thickness of ~300mm (inc. 70mm of battening and cladding on the outside skin) and I’m under the impression that ICF would struggle with that.  
 

Stick built is the default option, I’m exploring alternatives in part as a validation exercise but I’m learning tons along the way.

 

My investigations so far indicate that a SIPs on site blank panel build would use 175mm PU SIPs or 200mm EPS SIPs to yield a u value of better than 0.17.

 

Cost wise, and this is very broad brush, (and includes walls, joists, chipboard flooring at first floor only), it appears that:

 

1. Get a company in to do the lot and it’s just over 100k.  Game over.

2. Have a different company make it in factory and deliver it for me to erect and it’s about 52k.

3. Buy blank PU SIP panels and build it myself, buying in joists etc. from other suppliers will cost about 35k.

 

Each of these options require a fire board skin, cladding, internal battening and osb/plasterboard (I want good solid walls).

 

So, next step is to repeat the same process for stick built.  At present I’m struggling to work out a stick built wall build up that yields a decent u value and the right thickness.  

[SteamyTea]

5 minutes ago, G and J said:

 At present I’m struggling to work out a stick built wall build up that yields a decent u value and the right thickness

Can you post up some dimensioned sketches of what you want to achieve.

Each thermal element does NOT have to meet building regs, so some areas can overcompensate for weaker areas.

It all comes down to surface areas and U-values at the end of the day.

[MikeSharp01]

3 minutes ago, G and J said:

yields a decent u value and the right thickness.  

That's a tough ask as the one controls the other. You know what our build up is and the resulting U value (a combination of PU and blown cellulose) and that comes out at 470 mm (ish). Maybe worth looking at making the internal dimensions slightly smaller and playing with internal features; vaulted ceilings, through views, clever decorations etc to make it feel bigger.

[saveasteading]

1 hour ago, G and J said:

the boom would have to arch over electric cables

Booms are only one type of machine. the simpler version and much cheaper type has the concrete pump as a trailer, and the pipes go along the ground.

 

1 hour ago, G and J said:

struggling to work out a stick built wall build up that yields a decent u value and the right thickness.  

I can't see how that is a problem, except for the reduced insulation at studs, but that is only 5% of the area and so compensation / trade off should be findable elsewhere.

 

I suggest that you are set on sips panels and see anything else as inferior.  

If you have decided on a maximum wall thickness, and stick build is falling short on your target insulation, by say 5%, then it is easy to compensate for that in the roof or floor.

[Iceverge]

@G and J

 

I've been loosely following this. 

 

The essentials are you want a low U-Value Wall, with minimal thickness on a site that constrains the use of high overhead machinery. 

 

If you really want to dig into the weeds on this I'd advise that you try thermally modelling the entire wall, not just a simple U value calculator, in order to account for thermal bridges.  Once you get towards any acceptable U values thermal bridging becomes really significant. Particularly around windows/doors, the floor wall joint and the first floor ceiling band area.

 

You'd be surprised how the promised performance of a SIP wall worsens, once taking these all into consideration, as SIPS often require solid timber blocking in these areas. 

 

 

 

 

 

 

 

[G and J]

1 hour ago, SteamyTea said:

Can you post up some dimensioned sketches of what you want to achieve.

Each thermal element does NOT have to meet building regs, so some areas can overcompensate for weaker areas.

It all comes down to surface areas and U-values at the end of the day.

I’ve noted that many peeps seem reticent about posting their plans so I haven’t posted so far, but I don’t see why not. 
 

Whilst I appreciate that we can trade off u values between different elements I'm taking the approach that by working each element we get the best info we can to fuel those trade off decisions, and as a spin off I’m learning tons of stuff too.

 

 

[G and J]

1 hour ago, MikeSharp01 said:

That's a tough ask as the one controls the other. You know what our build up is and the resulting U value (a combination of PU and blown cellulose) and that comes out at 470 mm (ish). Maybe worth looking at making the internal dimensions slightly smaller and playing with internal features; vaulted ceilings, through views, clever decorations etc to make it feel bigger.

We will give up room space if we really have to, but we’re not at that stage yet, and we think we’ve already optimised our layout for what we think our needs and preferences are.  God help us! lol