Boarding + insulating system-built loft

ed110220

Hi all, I plan to insulate and board part of my loft for storage, just part of it around the hatch. The rest I've insulated with ordinary loft roll.

The structure is a little unusual as it is system built with steel I-section joists running the length of the house just over 1m apart and then timber noggins about 50cm apart fitted into the steel joists onto which the ceiling boards are nailed. The noggins seem a non-standard size (75x30mm) I guess to fit the steel sections.

My plan was to heighten the noggins with extra timber to bring them up to about 100mm and then put 100mm loft insulation in, then Wickes Spaceboard (http://www.wickes.co.uk/space-board/invt/161280/) and then chipboard loft boards over the top.

Unfortunately my local Wickes don't stock the Space board, so I was thinking is there another better way of doing it?

I know you can add two layers of loft insulation - another at 90 degrees to the first and with extra timbers also at 90 degrees, but I'm reluctant to do that as due to the shallow pitch of the roof it's already not high enough to stand in at the ridge and I don't want to reduce it more than I have to.

WestonDave

I think B&Q do some loft boards that have a form of solid insulation stuck to the underside - not sure how that compares in price and performance (U value etc) to Spaceboard and chipboard. You are probably on the rights track - make the most of the 75mm by filling that and raising the level up to 100mm and then putting some form of solid insulation over the top.

http://www.diy.com/nav/build/insulation/loft-insulation/B-and-Q-Insulated-Timber-Loft-Board-L-1200-x-W-320-x-D-123mm-10647753

ed110220

Thanks Dave - I've already got the chipboard boards though! I couldn't find any timbers 30mm wide (hence why I thought it was a non-standard size) so I got 22x47mm which will make it almost 100mm.

Here's a photo of it with the original insulation removed:-

WestonDave

Which Wickes have you tried (apologies for a bit of "snooping" back on old posts) but I see you are in Bath which is where I live (I was checking whether you were in NI who won't have the subsidised Space Board). I know there is a Wickes in Chippenham, and also one at Longwell Green, both of which are accessible from Bath reasonably easily - I recall bringing my own spaceboard back from Focus in Chippenham!

ed110220

WestonDave wrote: »

Which Wickes have you tried (apologies for a bit of "snooping" back on old posts) but I see you are in Bath which is where I live (I was checking whether you were in NI who won't have the subsidised Space Board). I know there is a Wickes in Chippenham, and also one at Longwell Green, both of which are accessible from Bath reasonably easily - I recall bringing my own spaceboard back from Focus in Chippenham!

No worries for 'snooping'! I see which Weston that must be now I went to Longwell Green and they checked other local stores but maybe Chippenham wasn't local enough for them? I could get it from there if they have it so thanks for the tip.

Just to check, do you put that spaceboard down over the noggins and at right angles to them and then the same with the loft boards? I'm guessing that spaceboard is fairly hard and the noggins won't sink into/cut into it.

WestonDave

I'd salvaged some plywood shelves from work which I'd used in my previous house for loft storage, so I laid them across the noggins (right angles) and then put the space board and loft panels in the same direction on top. It was a bit of overkill really as the spaceboard is pretty tough stuff, but as I had them spare I figured it was easier to use them than haul them to the tip. So mine is now 100mm of loft roll type insulation, 20mm of plywood, 2 layers of space board and then some chipboard on top. One thing to bear in mind is that you will be raising the floor height in the loft so will need to think about what you do with the loft hatch. In mine, I put some 100mm joist timber round it screwed into the noggins (if you want a few very long screws try Langridges in Larkhall or Francis DIY in Moorland Road - cheaper than buying a load in a shed). That way its all secure enough to put a loft ladder on.

The Wickes at Chippenham is on the A420 roundabout - you can either go up the A46 and then along the A420, or out along the A4 to the edge of Chippenham and then follow the ring road (A350) up towards the motorway. There's a Wickes in Trowbridge as well which is fairly accessible but they probably checked that. It may just be that its the end of the winter and stocks are a bit lower.

WestonDave

One more tip - an old/cheap bread knife is good for cutting it if you need to depending on how the lengths match up with the noggins.