DIY ICF Construction - Bracing

[Conor]

10 hours ago, Alexphd1 said:

@Conor just a idea.

What insulation spec of ICF are you looking at? If your going for a high insulation build maybe possible to use basic eps icf then add on another layer EWI as @Stones done with amvic icf. My quick calculation was this would have saved me a fair bit of £ doing this with nudara icf instead of buying a wide block and the extra 150mm inserts to beef the uvalues. Also a lot faster to put up ICF. 

I will investigate this further myself for next build, as they say every day is a school day! 

 

Passive, so U value of 0.15 or lower. I'm looking at exactly that option. Standard ICF will 100mm EPS. I've just to understand how you can attach the EPS sheets to the ICF. Thinking a bead of low expansion foam plus a few mechanical fixings of some sort. I remember pricing it up a while back and the cost saving is in the region of a few thousand pounds!! 

[Conor]

29 minutes ago, Alexphd1 said:

Another idea.... say you add on extra 200mm EWI would it be possible to cut the ewi into a tight curve into the windows? i think this would be a nice detail!

 

Yes, planning angled reveals. Trim off EPS at 45degrees around the windows. Similar detail to the existing Edwardian townhouses further down our street. 

[scottishjohn]

yep thats it -and you can do that to nay wall ,polyblocks ,wood crete ,,blokcs etc etc

[Jeremy Harris]

The bottom line here is for anyone seeking advice to sift out all the stuff from those that have little or no practical experience from those that do.

 

If I were after advice on ICF, then I'd first of all take heed of those here that have built using an ICF system, as their views are massively more valuable than anyone who has not built using ICF.

 

With regard to bracing, then my view would be to take heed of the experience relayed here by those who have first hand experience of failing to brace walls.  What a manufacturer publishes on their website means diddly squat if the reality is that winds or pouring loads can dislodge an unbraced structure. 

 

Reading this thread there are opinions expressed by several people who have first hand experience of building with ICF, and their comments are worth 100 times more than those of someone like me that has never used the stuff.  In particular I would take heed of @jamiehamy, @AnonymousBosch, @Russell griffiths, @Triassic and @Alexphd1, as they seem to be the only members posting in this thread that actually have experience with ICF.  Some of the other comments may well come from just using a search engine.

[Alexphd1]

Regarding attaching ewi to eps icf have a look at @Stones blog, he mentions it there.

 

Cheers Jeremy, am I last on your list??? ??

[Stones]

On 28/05/2019 at 21:06, jamiehamy said:

Agreed however were not talking about bursts, rather stability and safety during build and during pour. 

 

In short @scottishjohn is advocating building this type of icf without bracing, implying that experience makes this possible. Where we are we often get 30mph gusting 50mph winds when the wind comes from the east. Something to do with the warm air on the Moor gathering speed coming down the Glen. It happened on the day of our pour incidentally. 

 

It's careless and worrying to suggest something can be done a certain way without cautioning on the limitations, hence my question on windspeed. 

 

I'm confident that this particular product and many other icf products would not withstand a night of strong wind without either major damage or movement. That's not a criticism of any product either. And I'm certain that if it fell on you from the first storey just before pour, you'd get seriously injured. @AnonymousBosch will concur. 

 

Icf builders will weigh up the costs and risks when deciding on bracing. It didn't even enter my head to build our icf without bracing just to save a few hundred quid. 

 

 

 

 

As much if not more time was spent bracing our walls and the corners than actually building the blocks to wallplate.  My contractor was very clear that attention here was critical to ensuring a successful pour.  Have a look at my blog for more info and pictures.

 

On 29/05/2019 at 09:23, Alexphd1 said:

Regarding attaching ewi to eps icf have a look at @Stones blog, he mentions it there.

 

 

I do indeed!

[Vijay]

Where can you buy adjustable ICF bracing in the UK? Googled Zonts and couldn't find anything in the UK

[gavztheouch]

If you make sure that there is plenty of vertical rebar in the joints would it matter how many lifts you do to complete the house?
 

I am thinking of ways of building an ICF house without the stress of pouring in large lifts with potentially inexperienced pump truck drivers. I also have no experience and there does not appear to be any experienced builders in Scotland.
 

I am building on a farm and we have access to a tractor, telehandler and 13 ton digger. Just trying to think of ways I can do this with just myself and one other person. 
 

Tractor could have a pan mixer on the back which would give roughly 0.7 cube of concrete per mix. That would fill 4 to 5 lengths or so of NUDURA at 2.4m long but just one block high. I reckon in a day you could easily fill two layers of NUDURA block all round my proposed house. I would need the digger or telehandler to lift the concrete up to the wall. Could modify a bucket to hold the concrete with a flexible 2” tube to pour like a concrete pump but just using gravity to feed through, with a sliding gate to control the flow.

 

if I was feeling confident I could order a lorry load of premix and use the digger to lift into place with the special bucket.

Is this a bad idea?
 

 

 

 

[Gus Potter]

Hello Galvtheouch.

 

I'm kind of local to you, but more from the Biggar / Agricultural area so can see where you are coming from.

 

If you want to do ICF as a superstructure? again I can't see this panning out financially unless you own the ICF and concrete company.

 

While it sounds attractive to mix your own it's frankly bonkers to spend all the money on ICF and think you can hand batch stuff that won't leak. You can make a concrete wall pretty water tight if you get the grading of the aggregate / cement / water content / correct compaction under control but this is not for the lay person. If you want to know more ask a Water Board Engineer how to construct an undergound water tank that does not leak...is a basement etc not just a tank with some added insulation the reverse of this?

 

You seem to have an agricultural type backgound and thus practical skills that a lot of folk would give their back teeth to have. What about just going back to say timber frame, use a 150m kit which you can build yourself, erect with your telehandler, seems like you have a lot of space so perhaps use the digger for the founds, pan mix the foundation concrete, check your mix, make the savings elsewhere and utilise your practical skills.

 

Just as an aside.. it's well worth looking at the stuff that Jeremy Harris has posted.

 

I'm probably going to get pelted for this but to simplify. ICF and low U value house basement / slab / basement slab  designs are basically pinched from industrial building / cold formed store design. In fact, is not a lot of current design based on lots of stuff and design codes / principles from Canada, North USA where they are used to dealing with low temperature, permafrost, mitigating heat loss etc.. we just rebrand this in the UK, make it sound difficult and charge more for it.

 

In terms of ICF. If you are doing a basement then in Scotland I can't really see this panning out profitably unless you live in the centre of Edinburgh even then, there are not many real live jobs as the ground conditions are difficult. Even the superstructure, I can see some of the merits but..

 

All the best

 

 

 

 

 

 

 

 

[Alexphd1]

Hi Galvtheouch,

 

I dont see any mention of basement in your post above so will ignore that. The external coating ie render, cladding etc is your waterproof layer in a above ground icf build. Icf basements is a total different ball game and there is many existing threads on this.

 

I am building (build 2) in Scotish countryside and a diy icf selfbuild basement not only adds up financially but utilize the site to the best layout for me.

 

 

 

No problem in doing what you suggesting a guy on this forums predecessor ebuild done exactly that on the outer hebrides. He bought a self loading 1cu mixer and self mixed all the icf build himself. Dont underestimate the workload though he questioned in the end if it was worth it think he would have done single block on side with EWI if starting again.

 

Not sure on the practicalities of ordering a load of premix then using a digger with concrete pouring ladle set up, you need good control for firing the concrete

into the 150mm gap plus the time to use use the full load you could end up in one big mess. 

 

To hire a concrete pump for a day 700-800 pounds and premix will be mixed to consistent standard. You could cut weeks of hard work from your build. Is it worth the hassle?

 

 

[Gus Potter]

Good post Alex.

 

Interesting stuff that it worked out financially for an ICF superstructure in Scotland. How did you make that stack up? Do you have a trade connection or can this be done by a self builder from "cold"?

 

Have you had a chance to finish it all off and look at it holistically, installing the services and so on. How future proof is it.. can you run an extra cable in the wall without major drama or are you a bit stuck on any alteration / extension you may want to make? 

 

Good point you make about the Scottish Islands, I have family that live in the islands and it is a completely different economic ball game. You have the ferry  / transport cost, there is, if you are lucky a couple of folk that have a 16 tonne 360 digger..you need to make friends with the local dump.. try getting a skip to Tiree?..  and trying to get someone with a pecker when you hit the granite dyke. A granite dyke is an igneous intrusion. Often you'll find that the earlier islanders avoided building over a hard spot where the hot granite from deep in the earth made it's way to the surface. If you are unlucky this will manifest right under your found or septic tank and make life difficult. That is partly why there are gap sites on the Islands, but more often than not it's to do with who owns what and family history.

 

Alex makes another good point about buying a mixer and doing it your self..been there, but yes when you look back you may have lost a few quid but it's that thing about knowing you have built you own castle with your own hands and that has value, it enriches life, so perhaps appreciate that?

 

Just to touch briefly on ICF bracing. It's essential, firstly someone could get killed if it falls over..concrete is heavy stuff.  If it bulges/ start to tip a bit then it's very difficult to fix in the heat of the moment. The key here is to make sure that you have someone , perhaps an SE who has the authority to oversee the operation.. that comes at a cost but.. there is an expression that is used to describe piling contractors and it is "who dares wins the job"..so if you employ someone to do the pour make sure you know where the risk lies and who is responsible if it goes wrong. Better to brace it to death and save the aggro.

 

 

 

 

Edited September 5, 2020 by Gus Potter
clariification on geotechnics

[Alexphd1]

I have no trade connection or own a icf company, I am a fisherman.

 

I wanted a system I could build myself and as it is a large build, icf was the best solution for me integrated with a diy insulated raft. Timber frame costs where ridicules for us by the time you added in the steel work. Single block with ewi would have been a good option but decided against it in the end. A heavy insulated air tight house without relying on taping plastic sheets was also a attraction which is easily achieved with icf on the principle fabric first approach learned on here.

 

Future proof is a tricky one, I have came to the conclusion there is no such thing it's just snake oil used by salesman pushing expensive systems but we have build everything with ease in mind for future. Large eaves upstairs we can drop new cables down 2 inch gap on icf wall (2 inch batten between icf and plaster) steel conduit in block build garage that goes direct into the large eaves. Large easy to work areas for mvhr, ST station etc. We even looped every individual PV panel into to the loft space so if one panel fails we can loop it out pretty easy.  As for the need to add a extension we have tried to design that out at the initial design stage.

 

Agree with Gus on the over brace option but blow outs on icf is not uncommon although thankfully bracing falling over is. A blow out is not the end of the world and can be fixed during the build (we didnt have any blow outs with nudara icf)  I strongly recommend anybody considering a icf diy self build, visit as much sites during concrete pour day as possible and learn some good practices ie small constant pour lifts is better than just holding the nozzle in one bit and filling to to the top. 

 

 

 

 

[ToughButterCup]

5 hours ago, Gus Potter said:

...

Have you had a chance to finish it all off and look at it holistically, installing the services and so on. How future proof is it.. can you run an extra cable in the wall without major drama or are you a bit stuck on any alteration / extension you may want to make? 

...

Just to touch briefly on ICF bracing. ... Better to brace it to death and save the aggro.

 

 

Yes, its (Durisol) easy to mess about with: our extension will (4 years from now) be easy - already planned, piles driven in anticipation, two years ago. Services to the extension are already in place.

 

Bracing - its a faff. I've seen bracing as a simple Europallet, other bracing that was two layers of 22mm sandwiched between 2 lots of  4 by 4s , and proper professional steel bracing (on Durisol). And of course, the most common of all: none.

 

We had seven blow-outs, 6 very small, quickly sorted - jam a shovel against it - screw a bit of timber aginst it - that sort of thing , and one that was caused by the combination of criminal damage and failure to brace. I am a bit annoyed with myself still - because I saw the guy hitting the blocks with a lump hammer - that I did not insist on bracing.

 

Brace it to death as @Gus Potter says - and I would add, plan for what you are going to do with the bracing when its taken down. We are still re-using the 4 by 4s and  sheets of ply. Overall, the bracing cost us nothing extra. We would have needed the 4 by 4 and the ply anyway.