Using attic stilts for attic flooring

Lekrub

I'm looking to floor out most of the attic soon. The water tank takes up most of it, so will need to go tight to the eaves.

Has anyone used the attic stilt kits you can get from B&Q or woodies? They raise the floor to a height to give an air gap to avoid condensation, but they look pretty weak. Be good to hear from someone who has used them.

fred funk }{

Have them in my side attics an they're sturdy.

Wheety

I wouldn't walk on them but I do have some for storage.

MAJJ

fred funk }{ wrote: »

Have them in my side attics an they're sturdy.

You could use OSB insulated boards screwed to rafters . This will be overlayed earth wool between rafters. Means less height and no stilts.
Hope it helps, it's what a professional company has recently quoted me.

Also, if you go right into eaves with earth wool, this will block your ventilation and you may need to consider tile vents.

raxy

I didn't trust the loft lifters for walking on when I did my attic. I got 100mm PIR insulation board & put T & G OSB flooring over it. cost a lot less than it would have been to use lifters & no worries about the floor giving way

Lekrub

raxy wrote: »

I didn't trust the loft lifters for walking on when I did my attic. I got 100mm PIR insulation board & put T & G OSB flooring over it. cost a lot less than it would have been to use lifters & no worries about the floor giving way

This was kinda what I had in mind first. With maybe lengths of timber across the joists to raise the floor up. It will only be a couple of sections cos of the eaves as I mentioned

raxy

no need raise the floor if you use PIR insulation, you'd have the insulation between the joists & the boards over.
100mm PIR insulation is equivalent to 200mm insulation roll.

colm_c

raxy wrote: »

no need raise the floor if you use PIR insulation, you'd have the insulation between the joists & the boards over.
100mm PIR insulation is equivalent to 200mm insulation roll.

Considering a similar project myself.

So replace the rockwool with PIR and screw the boards to the joists.

Lekrub

raxy wrote: »

no need raise the floor if you use PIR insulation, you'd have the insulation between the joists & the boards over.
100mm PIR insulation is equivalent to 200mm insulation roll.

This does sound easier but I don't have the cash to redo the whole attic insulation. The house is C1, so not too bad. I might possibly see about replacing in sections where I'm putting the floor for handiness.

There seems to be alot of rockwool type insulation in the attic. It goes up a far bit past the joist. I'll have to measure it tomorrow. Good for insulation I guess, bad for this boarding job.

Colonel Claptrap

How did you get on?

Lekrub

Didn’t get a proper chance to get up and have another go. I’ll measure and post a pic this weekend

Lekrub

So got up to the attic and took a few pics and had a closer look. There seems to be between 100-400mm of insulation at different places up there. You'll see its not rolls of insulation but a cover all loose type.






So as the insulation is pretty high over the joists in most places, it will really compress with boarding. Do you think this will cause a moisture problem?

I might just do around the water tank (which takes up most of the space) and leave the sides, they're pretty wild.

randy hickey

Hi Lekrub, I can't speak to your attic flooring query, but a couple of things jump out from your last picture.

I don't think the area directly underneath your header tank should be insulated, but I do think that the white plastic flexi-duct in the background should be insulated.
I am assuming that it is carrying the warm moist air from the extractor fan in your bathroom or ensuite to a vent tile in your roof.

Sorry for the off-topic.

Lekrub

randy hickey wrote: »

Hi Lekrub, I can't speak to your attic flooring query, but a couple of things jump out from your last picture.

I don't think the area directly underneath your header tank should be insulated, but I do think that the white plastic flexi-duct in the background should be insulated.
I am assuming that it is carrying the warm moist air from the extractor fan in your bathroom or ensuite to a vent tile in your roof.

Sorry for the off-topic.

Hey cheers for the advice. Your're right, that's from the ensuite shower and goes to a vent tile. I'll have to search to see what type of insulation for that.

On that same duct, should it go in a straight line from the extractor fan to the roof vent, or will the hot air still rise if the duct is laying on the ground for a bit (maybe 60cm) before going up to the roof?