Expanding foam as insulation

Macker

Is expanding foam a good insulation? I have a cavity wall of about 60 blocks in my shed and I Wat thinking of filling the cavities with foam rather than lining with fiberglass, any idea how many tins I'd need and where to source?

Markcheese

I'm pretty sure it's not to be used in confined areas ... ( Like a cavity wall ..) , the propellant ( butane ) can blow ... There was a clip of someguy blowing up his kitchen with it ,

listermint

Not a good idea. You'll never fill all the gaps it's pointless and would ruin any chance of filling the void later on

Ak84

Concrete is the only thing to fill them blocks with.

Lumen

Do you mean "cavity wall" or "wall of cavity blocks"?

GreeBo

It sounds like you are still in the building phase, if fiberglass is still an option, so why not just use pir sheets?

the_pen_turner

it would cost a lot in foam. why not get it pumped with polibead

Macker

GreeBo wrote: »

It sounds like you are still in the building phase, if fiberglass is still an option, so why not just use pir sheets?

No it's an old shed I'm turning into a mancave, two walls are insulated with fiberglass, one is a dividing wall so I'm not going to bother insulate, front wall is 16X8 cavity blocks but has 2 windows and a door, screw fix are doing a job lot of foam for 77 euro, thought it might be an option

GreeBo

If it's just plain blocks now the easiest thing would be to board or with insulated plasterboard.

Macker

GreeBo wrote: »

If it's just plain blocks now the easiest thing would be to board or with insulated plasterboard.

Its bare wall now with new windows and door, I have to create a reveal so it's going to be lined with 3X2

GreeBo

Macker wrote: »

Its bare wall now with new windows and door, I have to create a reveal so it's going to be lined with 3X2

So just fit PIR boards between the 3x2 and board over, same as any other wall.

Trying to do that well with expanding foam will be a disaster IMO.
If you are hooked on foam then get someone in to foam it for you, or buy a foam kit and DIY.

the_pen_turner

GreeBo wrote: »

So just fit PIR boards between the 3x2 and board over, same as any other wall.

Trying to do that well with expanding foam will be a disaster IMO.
If you are hooked on foam then get someone in to foam it for you, or buy a foam kit and DIY.

can you buy large cylender of foam and do it yourself. i have a job at home that it would be really usefull way of doing it

Macker

GreeBo wrote: »

So just fit PIR boards between the 3x2 and board over, same as any other wall.

Trying to do that well with expanding foam will be a disaster IMO.
If you are hooked on foam then get someone in to foam it for you, or buy a foam kit and DIY.

Yeah I'll probably end up doing that, I just wondered was it an option

GreeBo

the_pen_turner wrote: »

can you buy large cylender of foam and do it yourself. i have a job at home that it would be really usefull way of doing it

Yep, you can, comes in two tanks that mix at the nozzle.
http://red-letter.ie/product-category/spray-foam/kits/?gclid=CjwKCAjwmKLzBRBeEiwACCVihnNSe0wj61HEgR9OyLqIfdkgKsHfBja4LTPRnFMK5Nqz6XOxW30c7BoCH9QQAvD_BwE

Macker wrote: »

Yeah I'll probably end up doing that, I just wondered was it an option

It is an option, just a bad one

D13exile

As Greebo suggested, insulated plasterboard is the best option. Either fix it with adhesive or dot and dab. Alternatively, batten the wall and fix to the battens.

The slimmest insulated plasterboard is 38mm but it can be bought much thicker than that. The more insulation, the warmer it'll be but you'll lose room space.

whizbang

If you fill the cavity then you loose the ventilation / evaporation that prevents moisture travelling across the bridges in the blocks. So any moisture that hits the outside, will travel through to the inside.

Otherwise you must totally waterproof the outside, if the cavity is filled.

johnayo

whizbang wrote: »

If you fill the cavity then you loose the ventilation / evaporation that prevents moisture travelling across the bridges in the blocks. So any moisture that hits the outside, will travel through to the inside.

Otherwise you must totally waterproof the outside, if the cavity is filled.

But surely That only applies to a cavity wall and not for a cavity block built wall.