Looking to re-board my loft space

[CmdrBond]

Cheers for that, I forgot I could simply knouck off the odd edge.

I don't want to put anything under the tiles that would act like a sponge though, as that could hide any problems and make them worse.

I'll sort the floor out first and have a look at the roof after - once I have a solid platform to stand on.

Going to use self cutting screws, but will pilot the joists as well. 100mm has been suggested for joining the joists - what about for the floor? I am thinking ~60mm?

 

[mointainwalker]

, put polystyrene foam panels in (or rock wool), then possibly plasterboard the inside (you could use 3mm ply instead) to retain it.

I have to disagree with this advice from davelowe.

It is just plain stupid to insulate the roof when the ceiling is insulated. You gain nothing in heat energy saved, you lose the cost of the material and the work involved.

 

[freddiemercurystwin]

No disrespect meant to davelowe1977 but all of his posts show a little naivety and lack of experience and would respectively ask that he backs out gracefully from the thread. They are adding nothing but more confusion and miss-information to an already confused OP/thread.

 

[CmdrBond]

OK, here is the plan.

I am going run one layer of the original insulation inbetween the joists, being careful not to bury any cables and then cross batten with 100x47mm lengths at 400mm centres, making sure all joins rest on a joist. These will be fixed with 100mm screws at a 45o angle starting about 25mm up the timber.

I will lay the other layer of insulation between the battens and then lay either flooring packs or cut down 2440x1220mm sheets of 18mm chip, securing with 60mm screws and again, all joins will be across timber for maximum support.

Does that sound OK?

 

[freddiemercurystwin]

Fine, although make that about 35mm instead.

 

[CmdrBond]

Fine, although make that about 35mm instead.

I presume that is in response to:

...

These will be fixed with 100mm screws at a 45o angle starting about 25mm up the timber.

...

In which case I have one question.

If I am using 100x47mm edge on and get my 45o angle spot on, will the screw not be exiting the 100x47 to one side as apposed to more centrally? Or is this the idea?

 

[freddiemercurystwin]

Yes that's fine. You're really worrying too much, it'll all be nice and tight once the boards are screwed on.

 

[CmdrBond]

Cheers

 

[CmdrBond]

This might sound like a stupid question, but hey ho...

The 100mm screws that join the timbers together, should they have a thread all the way to the head, or should they have a section of unthreaded shank just before the head?

 

[freddiemercurystwin]

they should have a section of unthreaded shank just before the head?

 

[CmdrBond]

Time for another question...

Up until now I was planning to join the new joists to the existing ones by using 100mm screws at a 45o angle, however...

I was in I was in B&Q last night and stumbled across these...

Abru Purlin Ties (L)162mm x (W)20mm x (H)20mm

Right Hand - Left Hand

My question(s)

1. What size screws would you recommend if using these? - I am thinking 30/40mm (~1 1/4" / ~1 1/2")
2. At what distance would you fix them? Assuming all joists are at 400mm centres, every 1, 2, ... 6 joists?
3. And would you use 1 or 2 ties at each joint? If one I presume they would be alternated from side to side as you work across the joist.
4. I know which of the 2 methods is cheaper, but which is better? 100mm screws at 45o or Purlin ties?

Many thanks guys.