Increasing the loft insulation

[PDrawmer]

The loft insulation in our house is approx 150mm laid in between the 100mm ceiling joists. which are just a bit further apart than the width of the rolls that were used. So there's a small gap along each row.

I want to increase the insulation, and to store stuff in the roof. So I'm concerned about compressing the insulation and making it less useful.

What's the best way to do this? I know that if you compress 200mm into 100mm then it's only as effective as 100mm.

So, are there other products I can use on top of the existing ceiling joists that will take light loads, like me walking on it?

Are any of the foil products any good?

What's the current building regulation minimum? (as a benchmark)

The roof has eaves vents all round, so I don't want to insulate the rafters.

 

[noseall]

you can use rigid board insulation, but you have to make sure it is tight fitting and the joints are taped.

the risk of air moving around rigid board insulation is greater than that of quilt so there can be no gaps.

still or trapped air is a superb insulator.

air that moves over a surface, cools that surface. this is why the trapped pockets of air in fibreglass quilt insulation are so effective.

 

[^woody^]

If 200 insulation is compressed to 100 , its not as effective as 100 - more like 150 - 180.

Then you've got the timber boards, and then the various boxes and other stuff stored on it.

So there may be some slight loss on paper if you sat down and worked it out, but in real terms you are not decreasing the insulation values by anything significant

 

[xrv750]

my house was the same when i moved in so i bought loads of 3 x 1.5 and fitted them the the joists already there and was able to increase the insulation to 250mm and then lay floor ontop of that all.