Rick734

Thanks guys - super helpful thoughts. I'll run them past the chippy today and see what he thinks 😃

Thanks @MortarThePoint - apparently a diaphragm to prevent racking or something like that. Pretty sure he's overengineered the whole thing but better safe than sorry I guess... Helpful - so basically glue and nail then to prevent any chance of rubbing at all...

Couple of pics for reference...

Evening all, Just wondering if anyone can advise with a flooring query. I'm doing a TF extension on top of existing single skin garage walls, and the SE has specced a 9.5mm ply diaphragm over the joists, with flooring substrate to go over that (nothing specified for the actual flooring substrate so was going to use 22mm Caberdek). My chippy was saying they'd obviously glue and nail the ply onto the joists, and will use 63mm nails down into the joists through the ply anyway, but was then asking if I want them to glue the chipboard down onto the ply as well. Any thoughts on this? I just want to prevent any squeaking or movement - is adding or not adding glue between the ply and Caberdek likely to have any impact either way?... Thanks Rick *edited for clarity

Thanks for that @Nickfromwales - apologies for the delay! I've got some STS 12.5mm insulation board - would you normally ply behind that board as well? It does have extremely high compressive strength but maybe not so much 'bending' strength, if that makes sense...

Thanks, got it. Don't think I ever took it out of that noggin (just leant the top half back) so should still be correct. Now onto boarding...

Saw you mentioned it in a previous post and it was on offer in Screwfix so... 🤷 Aha will check that, thanks 👍 - don't remember seeing a lower tab so will check

Thanks @Nickfromwales - super helpful. I think in this case I'll leave them off then - gives me 'access' from the front to the fixing points should I ever need them. Added some Sikaflex EBT and 3 chunky screws down each side, let's see what happens! Hopefully never need to get it out. Great point about the demountable cistern as well - had no idea it was so simple to remove...

To jump on the back of this thread...just installed a Geberit WC frame in my downstairs WC. I did it the wrong way round and built a tight framework first to shoehorn the frame into and then fix, but it works. The only thing is I haven't yet fitted the top 'rail' (Which can be seen on the LHS) - anyone know if this is essential? As far as I can see it doesn't do all that much and prodtrudes out the front by 2-3mm, thereby pushing the backer board off the wall slightly when I fit that, so I was thinking of leaving it out. Thoughts please? Edit: the 'rail' is the blue bit sitting on the floor leaning against the wall, for clarity.

e.g. similar to this image:

@Russell griffiths Images attached - overall porch size is 7.2x2m approx. So pretty small as flat roofs go. Having looked at it last night I think I might go down the route of lifting the ledge plate just enough to get all fixings into the blockwork, and then use a long-leg joist hanger to drop down below the bottom of it to take the roof joists at the right height. Sound sensible?

Potentially, but my understanding of a masonry hanger is that it's bedded in and nailed down through the top, before the brickwork above is laid... so not very feasible?

Just to clarify - the main fixing point for the joist hangers would still be in the main ledger plate, but there'd be a few nails into the bottom fillet piece for stability and extra strength. Id attach that piece of timber with straps/plates or long screws up into the bottom of the actual ledger plate.

Thanks Russell/Save, it is a decent size opening and agreed definitely not ideal to drill into it. Might be able to keep the ledger plate high enough to just fix into the blockwork if I can use long leg joist hangars to drop down to the right level - any idea if that's acceptable? I guess they'd be hanging down off the bottom of the ledger plate by approx 150mm to get the heights right...maybe could fix another piece of timber to the bottom of it for extra strength/rigidity...does that make sense? Something like this:

Thanks, it spans approx 3.6m which is the opening from the porch into the hall. Happy to go the resin route, was just debating the pros and cons of either so thanks.