House extension out of concrete panels

[ARW]

This sounds like a poor investment into your own asset

 

[Hfd Cattle]

If a job is worth doing .....surely it's worth doing properly ?

 

[f0ster]

you can get exterior facing in any finish you require, exterior insulation is applied, then a layer of concrete, (sprayed on) then a layer of the finish you want, (bricks, sandstone etc) you then remove thin strips of the finished layer to give an appearance of brickwork with concrete as you would expect to see from a brick/sandstone built wall,

 

[f0ster]

they are printing houses now with a 3d printer, a gantry is erected and it starts an the base working up the way printing inner and outer walls with cavity, it uses concrete with reinforcing mixed in,

 

[glasshouse]

they are printing houses now with a 3d printer, a gantry is erected and it starts an the base working up the way printing inner and outer walls with cavity, it uses concrete with reinforcing mixed in,

Must be a big printer

 

[bobk]

A decent bricklayer would whack that up quicker and cheaper imo , my son would

 

[Lakesdigger]

If you want it to pass building regs then you'll be in for an awful shock. Even if they would let you use panels by the time a structural engineer has done the steel design it'll be dearer than blockwork. Let alone the fact blocks are easier to work with and course in for dpc and around window openings etc. That's without insulation and internal and external finishing.

 

[TWF]

ICF Insulated Concrete Forms. Cheap and quick to do. We have just done a Dutch barn conversion with them. 4" insulation 6" concrete 4" insulation.

 

[Mur Huwcun]

Footings, slabs and blockwork will only be peanuts compared to the rest of the build anyhow which you will need anyhow no matter what you use. Do it once and do it right.

 

[TripleSix]

"non standard construction"

Banks and insurers don't like it.

Try insuring or getting a mortgage on a prefab house...

 

[George from SJM Planning]

Like many on here have said you are taking a risk on it not passing building control inspections, causing issues with damp, fixings of fenestration and internal and external finishes.
If it is to make an architectural statement then by all means explore the option but with so many other alternatives that have been tried and tested I am sure on a cost basis there is something just as cheap.
Do you need any help with the planning permission?

 

[br jones]

Cold bridging will be a major problem

 

[Ffermer Bach]

I’m looking at knocking an aged conservatory down and then putting an bigger extension on the farm house in its place. I haven’t asked an architect yet or local planners so only thinking out loud at the minute, but has anybody ever or know of a house extension built out of concrete panels. I’m looking at something that’s 2 story. As a stand-alone basically it would be 6m x 10m give or take and be 6m high.
Ive spoken to a concrete panel supplier and basically they make 150mm thick reinforced panels x 1m high and any length up to 8m for roughly £250 each. This means I can get the 3 external wall panels for about £7,000. This includes 1m of panels underground for foundations. These would be held in place by metal gurders on each corner and in the middle of the 10m run.
We can set these into the existing farmhouse wall to join the extension into the farmhouse. We could do all that ourselves with the assistance of a local one man band farm shed maker. We could also then put in the ceiling separating the ground and first floor as well as putting on a slightly pitched flat roof.
Very roughly fag packet figures we could do that for around £15,000 which is double counting farm labour we are paying anyway even if we don’t do this ourselves. Includes all metal work.

At that point I’d then get in some carpenters to create the rooms which effectively would be 3 upstairs and a single space downstairs and then obviously plumber and electrician.

Once that’s up and watertight then we’d knock through from the existing farmhouse ourselves before getting a plasterer and decorator etc. Finally we’d paint the outside of the panels so it doesn’t look like panels etc.

As I said I’ve not got drawings and not asked a builder for a quote using normal brickwork so I’ve nothing to compare to but 6m x 10m x 2 stories is 120 sqm so I can’t see it being less than £50,000.

Any views?

I would do it properly, either cavity blockwork, or if you want to do a fair bit of the work yourselves, timber frame (which you could knock up yourselves in the workshop), and it would make it easier to use foundation blocks, then you only need a bricklayer for the outer skin or cement board over the timber frame with a silicon (tight coat) render system over it. And if you want, tape and fill the joints inside so no plasterer needed.

 

[Ffermer Bach]

Local house builders are just going through certification of concrete panels for houses. They’re built in with insulation. So it is possible to do it.

And I have seen builders cutting out and replacing metal frames on council houses (built in the 70's) where the bottom of the metal studs have rusted through (loss of structural integrity), I remember British Steel advertising steel frame houses as being the way ahead, so I think, just because a system is certified now does not mean it will pass the test of time. Having said that, I have just put an EWI system on my house, so I hope that passes the test of time!

 

[Forever Fendt]

And I have seen builders cutting out and replacing metal frames on council houses (built in the 70's) where the bottom of the metal studs have rusted through (loss of structural integrity), I remember British Steel advertising steel frame houses as being the way ahead, so I think, just because a system is certified now does not mean it will pass the test of time. Having said that, I have just put an EWI system on my house, so I hope that passes the test of time

Oh dear just done a conversion with concrete panels and a metal frame but all signed of by building control

 

[dave160cvx]

ICF Insulated Concrete Forms. Cheap and quick to do. We have just done a Dutch barn conversion with them. 4" insulation 6" concrete 4" insulation. View attachment 929942

How did you find them to work with? is it mu cheaper and easier to use?

 

[TWF]

There are quite a few companies offering different ICF versions. You can get someone in to build it for you or do DIY and get some training. The product is very easy to work with and quick. You can clad it on the outside with what ever you want.
We had a firm in to put it up as we were plenty busy enough doing other jobs on the farm and build. Its also good to have a bit of experience on a large build for when things go wrong. You need plenty of labour about on the pouring days.

 

[Andrew1983]

What about using insulated box profile sheets? Easier to work with and they can look ok in slate grey, there’s a house gone up near some of our fields entirely from these sheets. At first I didn’t like it but it has grown on me. Fix them to a timber frame, put extra kingspan in the void and plaster board on the inside. Would hardly need heating.... concrete panels would just pull heat away all the time. Nice and cool in summer though lol

 

[TWF]

The good thing about ICF and we also used Hollow core concrete slabs on the first floor is the thermal mass of the whole building is very stable.

 

[Doing it for the kids]

What about fire?