Spray Foam Roof Insulation Any Good ?

ahll · Post by **ahll** » Wed Sep 30, 2020 6:08 pm

In the loft there is some insulation on the floor but none on the Roof in betwen the joists.

I keep seeing ads for Spray Foam but I wonder if it a good ideas as it seems like it would stop the wood breathing. I don't know much about it so I thought I would ask the wealth of knowledge here...

If foam spary is not the way to go what would be the best thing to use?

Rorschach · Post by **Rorschach** » Wed Sep 30, 2020 6:46 pm

Pointless having insulation on the floor and the ceiling. If you need more insulation add it to the floor.

Ken010 · Post by **Ken010** » Wed Sep 30, 2020 7:09 pm

From all I have read, this spray Foam is marketed as a method of securing slipping tiles and slates as well as offering Thermal insulation.

But? the spray Foam will vastly increase the potential for wood rot to develop and spread at the interface of the foam and any timber it is coating.

For years now, the advice is that roof voids must be ventilated by either purpose installed perimeter eaves vents or retro-fitted tile vents, leaving the loft void vented and during winter as almost as cold as the external air. The property below benefits from the effects of the loft ventilation laid on the plaster board or Lath and Plaster ceilings, as I recall there is no upper limit on the depth of the insulation you place on the ceiling Plaster board or lath and Plaster.

ahll · Post by **ahll** » Wed Sep 30, 2020 7:33 pm

Rorschach wrote: ↑Wed Sep 30, 2020 6:46 pm Pointless having insulation on the floor and the ceiling. If you need more insulation add it to the floor.

Doesn't doing the floor keep the heat in below the floor but wouldnt keep any heat in the loft room ?

Rorschach · Post by **Rorschach** » Thu Oct 01, 2020 10:19 am

Why would you want to keep heat in the loft? You don't benefit from it. Insulate the floor better and you will benefit, leave the roof as it is so it can stay dry.

aeromech3 · Post by **aeromech3** » Thu Oct 01, 2020 11:15 am

Agree with the replies but I have loft tanks so the area below them is not insulated to allow some heat to prevent them freezing (well I remember my childhood having to go up and break the ice in the tanks to allow the ballcock to fall and refill same); so to limit heat loss from around the tanks I have cocooned them with boards which also protects them from the loft ventilation drafts .

Ken010 · Post by **Ken010** » Thu Oct 01, 2020 7:40 pm

In the situation you describe, exposed loft mounted water, tanks I have seen on several occasions a Timber frame erected around and over the tank, this allows you to clad with [any] material then over clad with insulation, in effect making a Cocoon over and surrounding the tank.

To keep the tanks relatively frost free remove any and all insulation directly below the [yet to be built] tank enclosure.

Advisable to make provision when building the frame for maintenance access to the tank?

Some of the contraptions I have seen in operation and working are very unsightly, but because of where they are aesthetics simply do not matter, but the end result does