Fixing timber on top of bricks?

[Peter500]

I'm wondering whether there is a better way to fix my timber. I'm building an extension and currently doing the flat roof. I'm screwing the deck to the edge bricks and then other timber will also be screwed through this.

I've been using 60mm concrete screws so far, but if they hit the mortar then they're useless. I've also noticed a few bricks have cracked when I drilled them with my SDS drill, but fortunately, not he face. The bricks are 40N core bricks and I filled the cores with mortar on the final course. I'm planning to use 150mm concrete screws when I screw the timber, and counter bore them a little bit.

 

[catlad]

The standard practice is timber wall plate and galv wall plate straps.

 

[ree]

OP,
There are "Hold-down" straps/wall plate restraint straps available - & various clips that will tie-in the plate, the joist, and (in pitched roofs) the rafter.

 

[Peter500]

The standard practice is timber wall plate and galv wall plate straps.

I'm screwing to the outer skin. I don't have a wall plate, but my joists are strapped (every 2m). The OSB boards are screwed to these joists. The joists stop at the inner skin. It's just the edge (200mm), where I'm fixing directly to the bricks.

 

[noseall]

I'm screwing to the outer skin.

STOP!.

 

[Peter500]

STOP!.

What should I do instead? Glue? I've done half of the lower deck already.

 

[catlad]

It's just the edge (200mm), where I'm fixing directly to the bricks.

I wouldn't

 

[Peter500]

I wouldn't

So does this mean it doesn't need fixing at the edge? I was worried about uplift etc. I will need to fix some timber 200mm, a kerb and drip edge batten, and these would only be able to screw into 18mm OSB if there are no screws into the bricks.

 

[Diver Fred]

These or these.
If you cannot get to the wall plate fix the short end to the underside of the joists the long end to the inner leaf.
Fixing the wall plate to the top course of bricks is not strong enough

 

[Peter500]

These or these.
If you cannot get to the wall plate fix the short end to the underside of the joists the long end to the inner leaf.
Fixing the wall plate to the top course of bricks is not strong enough

Maybe my question wasn't very clear. My joists have restraint straps. My question is about the very perimeter of the roof where the bricks are. The perimeter will have 18mm OSB, 4"x2" timber and then another sheet of OSB. I guess my main concern is movement. If there are no screws then things may move with wind/weight. Probably not a major problem with EPDM roofing, but still not ideal IMO.

It sounds like the consensus is that it's not necessary to fix the edge? My joists don't extend beyond the inner skin and there's no over hang (other than the thickness of the fascia boards.

 

[Peter500]

STOP!.

Is it really this bad? Does this mean people don't normally fix the edges?

 

[Deluks]

Is it really this bad? Does this mean people don't normally fix the edges?

In buildings, everything expands and contracts with temperature. This includes your timber roof, when it moves, it will move your bricks too. (Oversimplified)

So the top of your joists are flush with the top of the walls? They are sitting 'inside' the walls rather than 'on top'?

 

[^woody^]

The walls support the roof, and everything to do with the roof is fixed to the roof, not the walls.

 

[Peter500]

In buildings, everything expands and contracts with temperature. This includes your timber roof, when it moves, it will move your bricks too. (Oversimplified)

So the top of your joists are flush with the top of the walls? They are sitting 'inside' the walls rather than 'on top'?

Thank you, that's very helpful. It should be possible for me to remove the screws that I've put in so far.

Yes, my joists are inside the walls. I can see why people usually have them extending further now. I have metal web joists, so They wouldn't be able extend through like timber joists.

So I would be relying screws in 18mm OSB to support the timber for the drip edge etc.

The joists are fixed to the inner skin (restrains straps and morar) and the inner skin is tied to the outer skin. I would have thought that the walls would move even if they aren't fixed.

 

[Deluks]

Does the OSB overhang the wall?