Loft Flooring and 270mm Insulation

Blue_Lou

Hi,

I am going to raise the joists for my parents, they are going to get 270mm insulation under the warm front grant. There is already 70mm of insulation there leaving 200mm to be fitted ontop.

I am trying to plan the best way to use the joists

Is the following viable?

http://i115.photobucket.com/albums/n305/bluelou/insulation.gif

Or would it be better if the 150mm (2"x6") was two 75mm beams perpendicular to eachother?

jennifernil

I'm not sure I understand your drawing. Having said that, if the insulation is to be rolled out between the joists then any extra timber you fit to increase the height of the joists will need to be placed directly on top of them, not at right angles to them. I take it you are doing this so some flooring can be put down once the insulation is in place?

Blue_Lou

Yeah that is right, I would like to put flooring on top of the floor. The reason it is at right angles to the other floorboard is because apparently it spreads the load of the woods weight.

I've been looking at

http://www.adriansslotcarworld.co.uk/Insulatn.htm

That seems ideal, however he 'only' insulated to 150mm, my parents will be getting 270mm so it is going to be more heavy and I need to make the loft as strong as possible, as cheap as possible

jonnyw_2

Forget it

You are going to have to use 8 inch timber to get the extra height. It will have to be 8 by 2 because 8 by 1 would be too waffy.

It will cost a fortune if you are doing a big area, be difficult to fix to the joists (you would probably ensd up having to fit noggins between the timbers for stability), weigh a ton and be difficult to get through the roof hatch.

The picture you linked to certainly doesnt show the depth being increased by 6 inches - they look like slate laths to me which at right angles would be about two inches. If you read it i think hes just adding an extra 2 inch increasing the depth to 6 inch.

In the same position I am doing away with virtually all the loft flooring, just leaving a little bit to get to the loft light etc and just put a couple of loose pieces of insulation over the small boarded area which i can pull to one side when i need to.

Once you put this depth of insulation into the roof you cant easily use it for storage.

Alternatively you could investigate making it a warm roof. I dont think that would be grant aided.

Mr_Proctalgia

I think it would probably be cheaper to go for a "Warm Roof" than buying all that timber and as said it will be a !!!!!! of a job to do for little benefit. There is loads of insulation on ebay at the moment BTW.

HTH

jennifernil

Both those posts are just exactly what I was thinking. What size are the joists at present? If they are insubstantial then it would be a very bad idea to put any extra weight on them.

Blue_Lou

They are 2 x 4. I have decided to add 2 x 2 onto each joist and strengthen it (making it 100mm in total) and compress the 270mm into 100mm and add flooring on top of it.

djohn2002uk

A better solution is as I did. Put 4 x 2 on top screwed with 6" screws. When you put the flooring down, screw to every joist, just a couple of screws in each board will make it very stable.
Increasing the joists to 8" will mean a lot less compression of the insulation.

sneekymum

ring you local council's Building Control office and speak to a Building Inspector

(unless you're planning to do it illegally)

djohn2002uk

sneekymum wrote:

ring you local council's Building Control office and speak to a Building Inspector

(unless you're planning to do it illegally)

Absolutely nothing illegal about increasing the size of the joists in your loft.
Or adding flooring on top.
Or adding your own insulation.
Or compressing it a little, because there is no statutory regulation to say you MUST have any insulation at all (Except in new builds). Just recomendations.

jonnyw_2

I just wonder whether there is a market (unless it exists already) for a flooring product with a built in enhanced insulating property. Or an insulating product you can walk on.

There must be plenty of people topping up at the moment who are having just the same problems with loft boarding.

Anyone heard of anything like this?