do it yourself Insulation

[deuce22]

Hi.

 

I have recently applied for planning and I’m researching about insulation. I haven’t gone through anything yet, with the architect or building control, so I’m not 100% sure on the thickness.

I’m building a timber frame structure and then cladding the outside and guessing it would need to be around 200mm.

I have fitted PIR insulation in the past and it was a horrible, time consuming job, so I am looking for alternatives. I have spoken with a company about blown cellulose and I’m waiting for an estimate. I asked if the equipment could be hired and they said nobody in the UK hires the machine to do it.

I’m planning to do as much of the work myself, so I don’t really want to pay labour for this.

What other alternatives are there and which ones can be done yourself.

 

Thanks.

[Mr Punter]

We have had PIR factory fitted but that was walls only - we still had to do rafters.  You maybe could get the roof done if it was made cassette style.

[A_L]

For the same insulating effect pretty much anything will be thicker, cellulose would have been 0.04/0.023 or 1.74 times as thick (or about 350mm). Rockwool batts, (RWA45/RW3) the basic type not the mineral wool/fibreglass batts sold specifically for TF are economical effective and DIYable. They would be about 300mm on the same basis

[Gone West]

If you used grey EPS slabs you would need about 280mm to equate to 200mm PIR. Don't know if you can hire equipment for blowing grey EPS beads.

Edited December 8, 2018 by PeterStarck

[deuce22]

Mr Punter.

The frame is being built on site (stick build) by a Carpenter and myself. The plan was to frame it, get it wind and water tight, do 1st fix and then insulate it.

 

A_L

I only estimated 200mm of PIR, but I don’t think it’ll be far off that considering that it’s just going to be cladded. What about spray foam insulation, has it got similar properties to PIR or does nothing else come close to it?

 

PeterStarck

The slabs could be an option, but when I used the PIR slabs before there was quite a bit of waste and it was very time consuming. I’d prefer to use some type of blown or sprayed insulation, but want to do the work myself. I’ll have to do some more research.

 

Thanks.

[A_L]

4 hours ago, deuce22 said:

What about spray foam insulation, has it got similar properties to PIR or does nothing else come close to it?

 

Only closed cell polyurethane foam comes close to PIR, I do not know of any DIYable kits using this. All the kits seem to be open cell of one sort or another and are only about as effective as Rockwool batts.

[CC45]

Do you need it be equivalent to 200mm pir?  Thats a lot of insulation.

[A_L]

10 hours ago, CC45 said:

Do you need it be equivalent to 200mm pir?  Thats a lot of insulation.

 

Not really, with thermal bridging of the timber fraction a reasonable build-up gives U=0.16. Not so low compared to people here.

[willbish]

15 hours ago, A_L said:

I do not know of any DIYable kits using this

Is this a closed cell DIY kit? Claims >90% closed cell content in the tech spec.

[A_L]

7 hours ago, willbish said:

Is this a closed cell DIY kit? Claims >90% closed cell content in the tech spec.

 

Based on the claimed performance it is as good as the same thickness as PIR board. It is however on a 'cost for equal insulation performance' three times the
price of PIR and six times the price of Rockwool RWA45 batts.

 

[willbish]

@A_L yep that is eye-wateringly expensive. 

The advantages are potentially a lot less wastage than PIR boards and can form an airtight barrier so some cost savings if the alternative is a membrane.

Any other advantages/disadvantages?

[PeterW]

1 minute ago, willbish said:

The advantages are potentially a lot less wastage than PIR boards

 

Its hugely wasteful as you cannot control the expansion, let alone as an amateur. @PeterStarck had some ridiculous number of bags of trimmings from his installation and that was a professional install. 

[willbish]

That's disappointing to hear @PeterW

 

Is there a way to limit the expansion by fixing a temporary board over the void while it expands?

 

I imagine trimming any excess back is probably equally a crap job as cutting PIR boards to fit.

[PeterW]

The problems with restricting it are twofold - you won’t get the full air:foam ratio so your insulation won’t be as insulating, and the chemical force of this stuff expanding is quite impressive .... 

[Onoff]

I insulated an old shed from cans...

 

 

What a f**king waste of time that was!