Slate, No felt, thin 'joists' what options?

[apul]

Its about time we insulated the loft. Currently has about 1/2inch of old fibre and its covered in dirt.

I am wondering if we are going to be limited to the types of insulation we can use due to having no felt and thin joists. There is no intention of boarding over or storing things up there.
The current joists wont hold my weight, they really are that thin. 2"x3" maybe. Would adding 250mm of fibre type insulation add too much weight? Will it collect too much condensation?

As for moving around up there, I will have to put some planks up from the one central A-frame to the edge.

What do you think?

Thanks

 

[MasterAbacus]

Your 2 x 3 beams are little wimpy.... but ive seen 1 x 3 borded over for storage.... Whats the supporting walls like under them? I bet they are brick..... For light storage shouldnt be a problem....

As for insulation.... as you have no felt, you could use that foil backed bubble wrap, stapled to the beams.... not only will it give you some decent additional insulation it will stop the dirt from falling too...

 

[apul]

Thanks. I'll look into the foil stuff. I presume I'll still have to leave a gap where the roof meets the wall for ventalation? If so how much? And how about the top?

I was maybe thinking about using Space Blanket, -fiber wrapped in foil, on the floor. Hopefully that'll keep quite clean as well.

There are to walls under the loft, just one room. Just the four sides of the original house. The rest is an extension. I think It will be possible to rest some boards from the brick at one side to the middle Aframe.


Thanks.

 

[Symptoms]

Apul - do you want a 'cold' loft or a 'warm' loft? As you aren't going to use the space there is little sense in not insulating at joist level - the heat from the room below will heat the loft space if you insulate at rafter level.

As for your 3 x 2 joists, if you're worried about them supporting your weight use a 'crawl-board', laid directly across your joists, to get about. 2 boards are better than one as this will allow for more graceful movement in the confined space. Word of warning - ensure the ends of the crawl-boards don't overhang the joists 'cos if they don't, and you put your weight on them, the board'll tilt causing you to loose you balance (foot through the ceiling time!).

3 x 2 should support the weight of your 250mm thick stuff, remember that the joists are not supporting themselves they are tied into a frame structure which lends great strength. Creating a 'cold loft' has implications for your cold water (and central heating expansion) tanks and pipework if you have any up there. If you do wrap these up with insulated jackets made from the loft stuff; pipes - use proper pipe lagging (the thicker stuff, not the cheap thin stuff).