loft insulation: joist depth and boarding over

[mike004]

1970s bungalow. The joists in the loft are something like 4 inches high.
Currently there is some old scratch "glass-wool" insulation to a depthy of 2 inches. The central part of the loft is then boarded over.

Modern builds use an insulation depth of 250 mm.
How can I implement something like this depth for my loft?

* I will have to do without loft floor boards; or
* I will have to squash the insulation -- surely this reduces the effectiveness.

Whats the secret to upgrading a 1970s build to modern insulation requirements?
Mike

 

[disinfo]

1970s bungalow. The joists in the loft are something like 4 inches high.
Currently there is some old scratch "glass-wool" insulation to a depthy of 2 inches. The central part of the loft is then boarded over.

Modern builds use an insulation depth of 250 mm.
How can I implement something like this depth for my loft?

* I will have to do without loft floor boards; or
* I will have to squash the insulation -- surely this reduces the effectiveness.

Whats the secret to upgrading a 1970s build to modern insulation requirements?
Mike

Hi There,

I'm in a similar situation.

Our house is a 1910 ish mid terrace, the ceiling joists are only about 60mm deep.

We want to get rid of the existing insulation and replace with new 170mm insulation, i would also like to at least part board the loft.

As you say, squashing the insulation will reduce efficiency.

I was considering laying the insulation then cross battening the loft but am unsure about what size timber I should use to do this.

I'm thinking that if i cross batten, at least the insulation wont be totally squashed, instead only every 400mm.