Letting timbers breathe

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CeeVee

CeeVee

Well-Known Member
Back in the day we were told not to pack anything between timbers in roofspace so the timbers could breathe...as they would get dry rot if not.
So...why are all these new regs saying we have to ram kingspan between rafters and over the top of them?
 
Unless it has changed you have to leave a 50mm gap at the back of the kingspan to let air circulate and is why a lot of new roofs are counter lathed if kingspan is the spec between trusses/rafters.
 
Sounds like your boarding a ceiling with all this insulation
& builder not marked the spars lol

back in the day the felt was black sarkimg or mono flex would not breath with this type of felt

Felts know are designed for all this insulation, if you have asloping rafters
With insulation in-between & over you Need to vent soffit
& abutment ventilators 50 mm air space with correct felt

Or no vent or air gap need to use a impermable felt this Wil allow air through the felt as such
 
Its good to know we haven't gone backwards then!
Oh and yes...before now the builders have insulated without marking out for us...
:cachetada:
 
It's also worth noting that insulation is the primary part of the regs these days. Everything else is subservient to getting the maximum insulation into a structure.

The 1992 regs contained a minimum life expectancy for new builds of 60 years. Subsequent regs have no minimum life expectancy, so make of that what you will!
 
imago said:
It's also worth noting that insulation is the primary part of the regs these days. Everything else is subservient to getting the maximum insulation into a structure.

The 1992 regs contained a minimum life expectancy for new builds of 60 years. Subsequent regs have no minimum life expectancy, so make of that what you will!
Click to expand...

had to google subservient :D
 
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