Loft, Purlin, Insulation...HOW.....HELP......ETC!!!!

[pimpslider]

Hello all....

After looking at various pieces of information I have finally decided I need to post something.

I am insulating my loft. Not a giant loft and I have no intension of converting it to anything other than storage space. The only thing is, before I board it I need to lay the insulation (roll). Now this is easy enough, but the 'Purlin' (I learnt that word recently ) seems to be in the way of insulating up to the eaves. There is a gap of around 3 feet from the eves to the purlin board. Yes, I said board..!!

Now, I'm not overly up on loft construction and what I have read is that purlins are the vertical beams coming from the roof to the joists. However, I seem to have a massive 4" thick piece of wood running the length of the loft stopping me from insulating behind it. I can't even get behind it. As the joists continue behind it there are also some intermediate battens, so if I were to push some insulation through it would stop way before it reached the eaves.

Pics show the big board which runs from all to wall, the intermediate battens behind the purlin (which I photgraphed by putting my hand through the gap, sorry about the spider !) and an image I made up (to scale) with dims of the joists etc.

So, how can I insulate behind the purlin? Loose fill? Insulation board?

Thanks

Pimpslider [/img]

 

[pimpslider]

Anyone? Anyone seen this before and can offer advise on insulating behind it? Anyone? Dust?

After more hunting, is this piece called a 'knee wall'?

 

[chappers]

I think some form of loose fill is probably your best bet, maybe not ideal but a lot better than nothing.

It looks like those small timbers running between your ceiling joists are noggins someone has put in to catch up the plasterboard rather than cutting it to end on a joist.

 

[Symptoms]

pimp - Micafil ... loose mineral granuals for loft insulation, £8 a (big) bag.

 

[pimpslider]

Cheers for the comments.

The thing is, how exactly am I supposed to get loose fill in there?

 

[JohnD]

cut a hatch in the knee wall and crawl behind it.

 

[pimpslider]

cut a hatch in the knee wall and crawl behind it.

But is it not structural? That piece is 4" thick (see diagram). This is my problem.

The only way I can think of getting loose fill behind it is by running/tipping it down some piping/guttering or sorts over the top of the purlin.

 

[JohnD]

it looks to me like ply sheet nailed to a piece of 2x4 or similar.

like the webs in a beam, most of the strength comes from the top and bottom rails, so you can make a hole in the infill without weakening it much.

preferably not at the edge

or you could maker several arm-sized holes and reach through.

drill the ply and see how thick it is. I bet 12mm or 18mm.

 

[pimpslider]

Originally I thought exactly the same, that it was a simple 12mm bit of ply, but I felt the bottom of it and it was 4" thick. I can't check the full thickness all the way up as I cant get behind it.

Like you said though, if I drill a hole in the middle then I should get some idea.

I'll let you know.

 

[pimpslider]

Well my christmas was fun, with me insulating the loft! I ended up forgetting the idea of 'loose fill' and just bought some 100mm thick roll.

The gap from the eaves to the big board shown was actually about 5ft! I managed to slide the insulation underneath and prod it further down with a broom handle!

I still don't really get the purpose of this massive board. I double checked the ends and there is no way at all you can get behind it.

Anyway, done now, so all I have to do now is part board it.

Happy New Year all!!

 

[Shytalkz]

Looks like a plybox beam; also looks like someone before you was thinking of converting it to accommodation, hence its installation. It basically will consist of a number of top and bottom horizontal rails, with uprights probably at around 300-450 centres for that depth, with ply nailed/glued on both sides.

It's a good job you didn't go drilling arm-sized or even larger holes through it. JohnD wasn't totally correct in his description as to how plybox beams work by comparing them to steel I/H sections, although it is better to avoid holes towards the supports, whether ply, straight timber, or steel, tis true.

 

[pimpslider]

Looks like a plybox beam; also looks like someone before you was thinking of converting it to accommodation, hence its installation.

LOL...well they were a bit silly then as I certainly can't stand up in there and I'm only 5'8"....unless they were a family of dwarves!

Cheers.