Just had loft insulation fitted, 270mm of the cheap and nasty yellow fibreglass type. Before installation I had lots of stuff up there, which having been cleared before the job, obviously needs to go back in place.
Everything was resting on top of 15x500x1200 chipboard panels across the joists, and as they were only about 70mm above the top of the ceiling, putting these back will compress the insulation somewhat in places - is this OK? Finding the joists under that insulation will be fun in any case.
What sort of PPA will be necessary doing the job - the installers had masks covering nose and mouth on.
This came up recently. No it is not OK, as 270mm insulation compressed to
70mm depth will be less efficient than 70mm insulation, basically because you'll have pushed all of the air cavities out of it. The only way around it is to build up the joists, to have a new, high-level system of shelving. It's something I am thinking of doing in my garage conversion, as I'd envisaged being able to store a little bit of stuff up there.
I'd love to upgrade the insulation in my house loft - but, like you, I have too much stuff up there - and so would need some new method of storage.
The masks are nothing special - though usually you have the rubber valve bit on it, so you can breathe out and keep the inside of the mask cooler. Only a few quid from B&Q. No need for an asbestos-style one - yet... ;-)
Well, that's annoying - I spend a fair amount of time up there as there's a lot of stuff stored there and space is slim elsewhere in the house, so I'm always up and down getting something or other. I don't fancy having to wear a mask and boiler suit the whole time I'm in the loft either.
How would I go about building up the joists, finding them is going to be difficult enough, let alone uncovering them to attach planks to.
I cannot disagree that what you say is theoretically correct.
The central part of my loft is boarded, over insulation level with the joists, with lots of stuff stored on it. Either side has a substantial covering of insulation. One cold day I went all round the house with a temperature measuring gun, to see if I could find any significant cold spots. I could not detect any significant temperature difference between those bits of ceiling beneath central boarded area, and those with thicker insulation.
Perhaps plastic boxes full of books, carpet off cuts and empty cardboard boxes aren't such bad insulation after all.
As my roof has a fairly shallow pitch, lifting the loft boarding would be pretty impractical, as the headroom would no longer be workable.
1.Build the joists up, relay the flooring and insulation. Neat, but a lot of woodwork.
Roll back the insulation thats above the joists, relay the flooring, and place the displaced insulation back on top of the flooring. Not very neat, but a lot less work and works fine.
Just remove excess insulation. Works perfecltly, except that you only get 3" or so of insulation. Other options better if youve got the spare time to do them.
How to build up joists: just lay more wood along them, on top of them, to bring them up to 27cm height. So you'd add 8" deep timber, or more. Screw into place, dont nail unless you want your ceilng to fall down. If you glue and screw it strengthens the joistwork up greatly too. Dont make the mistake sometimes seen of putting the new wood at 90 degrees to the old. And do expect cracking of the ceilng if its an old L&P lime ceiling, due to differential movement as you tighten the screws up.
Locate joists and attach vertical timbers between joists and high points on rafters. Above the required insulation level, add horizontal timbers between new vertical timbers and lower/outer point on rafters. Rest boards on new horizontal timbers to provide elevated shortage. (I did this before insulating the loft - much easier)
For the walkway, remove a strip of the fluffy insulation down to top of joist level. Replace this with rigid celotex-type insulation (50 thick) and board over for access walkway.
what you SHOULD have done, is aaksked first. The BEST way to do this is to fill between existing joist, then screw more at right angles, and fill between those then sheet over with something cheap like floor grade chip to help seal from draughts and carry any loads. And keep dust from the glass wool or water it is, down.
I would still be tempted to install cross joists and plate anyway if you can.
You wouldn't need to wear a mask/boiler suit just to access the loft. It's when you disturb the fibreglass and it sends up particles that you need a respirator. Once the dust has settled, you'll be fine.
What sort of timber would I need for this and how many? Before the insulation, the weight of the storage was spread across several joists on the chipboard boards and stacked, sometimes 8 banana boxes deep. I don't see it holding the weight myself.
Either method works. Crossed timber is a lot weaker for a given amount of timber than new timber running on top of the existing joists. The latter strengthens and stiffens the floor stucture considerably, and thats a definite good thing if you're using the space for storage -
1.Build the joists up, relay the flooring and insulation. Neat, but a lot of woodwork.
Roll back the insulation thats above the joists, relay the flooring, and place the displaced insulation back on top of the flooring. Not very neat, but a lot less work and works fine.
Just remove excess insulation. Works perfecltly, except that you only get 3" or so of insulation. Other options better if youve got the spare time to do them.
How to build up joists: just lay more wood along them, on top of them, to bring them up to 27cm height. So you'd add 8" deep timber, or more. Screw into place, dont nail unless you want your ceilng to fall down. If you glue and screw it strengthens the joistwork up greatly too. Dont make the mistake sometimes seen of putting the new wood at 90 degrees to the old. And do expect cracking of the ceilng if its an old L&P lime ceiling, due to differential movement as you tighten the screws up.
Everything was removed from the loft for this job - council have finally got around to doing it after years of pestering. After years of junk was just stuffed up there, some in boxes, some not, I'm surprised that didn't do a very good job of insulating it. Anyways, took us best part of two weeks to sort it and pack it, and chuck a lot of it out.
It has to go back fairly sharpish, it currently resides in 60 odd 40 litre boxes and is quite inconvenient to have about the place.
Why is it a mistake to add joists at 90 deg to the existing? - another poster recommends doing just that.
Remove fibreglass over a small storage area by the loft door. Replace with Celotex to fractionally below depth of existing joists. Cover with board, store stuff on top.
Celotex/Kingspan have about 2x the insulatory value of fibreglass AND is unaffected by loft draughts, condensation and so on. Loft draughts in cold icy windy days can reduce fibreglass insulation effectiveness somewhat.
For that amount of storage it might be worth renting storage space in a special storage depot, especially if you don't need instant access to the contents of your boxes. It would save all the effort and mess of re-arranging your recently installed insulation and it's really quite affordable for smaller units.
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