Foam Insulation

dendof

Looking at insulating dormer bungalow. Been told that foam insulatin is the way to go. Would others agree with this?
Starting to get quotes. What kind of questions should I be asking to ensure I get the best quality product, and what I pay for eg how to check afterwards?

Dudda

I presume it's a roof you're on about insulating? New or Refurb? If refurb it's a good way for creating airtightness which can be tricky in an existing building. If new you really should be putting in a correct airtight membrane that's taped rather than relying on foam.

For a new build foam can be costly as you've the option to design in cheaper insulation solutions. For example if it's a new build timber frame and you're using cellulose in the external walls then it's a no-brainer to use cellulose in the roof.

So ya, few questions:

• New or refurb?
• Where are you insulating or thinking of using foam?
• What thickness do you have or what's the build up?
• What's the total area you're looking at?
• What type of access do you have (eg attic with a small hatch or new build with lots of room before walls go up)?

dendof

Thanks for reply. Sorry, should have said what I was actually doing...

It's actually the walls I am looking at pumping with foam rather than bead. There is some existing insulation there and I was told that the foamfill is better than bead in this case.

• New or refurb? Refurb
• Where are you insulating or thinking of using foam? Walls
• What thickness do you have or what's the build up? Not sure of existing thickness
• What's the total area you're looking at? 3 bed dormer bungalow if that gives any indication
• What type of access do you have (eg attic with a small hatch or new build with lots of room before walls go up)? Upstairs part of dormer is floored with some insulation aswell.

Also just got a quote of €1400-1500. Not sure if this is good or bad.
This was just a quote based roughly on '3 bed dormer bungalow'. So not sure what exactly I am getting with this

BryanF

The only foam certified for cavities is far more than that price. Beads are tried & tested.

Calahonda52

The walls may be the least of your problem in a dormer bungalow

dendof

BryanF wrote: »

The only foam certified for cavities is far more than that price. Beads are tried & tested.

Is BASF Walltite what you are referring to here? Is definitely more expensive but looks to be very good and is closed cell. From what I've researched, I should stay away from open cell foam.

Calahonda52

dendof wrote: »

Is BASF Walltite what you are referring to here? Is definitely more expensive but looks to be very good and is closed cell. From what I've researched, I should stay away from open cell foam.

Is the existing cavity insulation lined with alu foil on both sides?

dendof

Calahonda52 wrote: »

Is the existing cavity insulation lined with alu foil on both sides?

No just board one side from what I've seen

Lumen

From what I found Walltite was the best of the foams. This was the result of my reading around.

https://www.boards.ie/vbulletin/showthread.php?t=2057830336

Maybe the famously leaky traditional Irish dormer bungalow will benefit from the lower air movement in a foam-filled wall (compared with bonded beads), but as Walltite is expensive you could instead budget for bonded beads and use the savings to get a reputable air tightness expert/engineer to sort out the rest of your structure.

A proper heat loss survey would be a good start.