Digmixfill

If everything was true the rafter position would be like this Hopefully the pictures show enough detail. This is the short side. The gap between the inner leaf and the old wall plate is 240mm. This is the longer side. The gap between the inner leaf and old wall plate is 305mm. The bits of new timber aren't in the correct positions, but are relative so will hopefully be a decent visual representation that the larger gap will cause the rafters to terminate much lower in the void behind the corbelling.

Cut roof. Currently with purlins and ridge board, but will probably become ridge beam with purlins removed.

I have new inner leaf with cavity against an external 9 inch solid wall. When I fit the new roof the ridge will be level and the new wall plate on the inner leaf will also be level. With the rafters sitting on the new ridge to wall plate line the gutter line on the bowed wall will be quite a way off on some places - up to 100mm bow. The building has suffered roof spread in its past and some parts of the spread have been repaired. Structural engineer didn't seem too bothered by it so it is how it is. When re-roofing a building where the eaves, wall plate and ridge don't line up how does one tweak the eaves end of things? I'm making the assumption that I can't just make the wall plate cock-eyed and call it done.

Just quickly checked and I can fit 150mm rafters without any issue. Because the outer shell is anything but straight the space between the current roof and the new inner leaf varies and in some places I could fit 200mm. This reminds me to post another thread about how to deal with this...

To keep increasing the rafter height and lowering the ridge beam position, at some point I will need to start chopping into my new internal walls to lower the wall plate. I can carve the nose of the rafter to fit into the space behind the corbelling, between the external brickwork below and the tiles.

Our rafters terminate in the cavity behind corbelling. I would think there is a limit where lowering the ridge beam height to accommodate the deeper rafters would cause the end of the rafter to kick up tiles. All of our second floor is room in roof and head height is limited in what will be a shower room. I can play with the space available to see what I can get in. Still no downsides to the idea though

Building control will be checking everything, as usual. Like most on here I plan to over insulate It's already designed to be a room in roof, so no storage space to lose.

Hello all, I've currently got 3.25"x2" rafters and purlins with a ridge to wall plate span of a little under 3m. I'm considering upping the rafters to 125x47mm and installing a ridge beam. I can only see advantages with the change. Then I think - If that is the case why aren't all room in roof ridge beam and not purlin? Are there disadvantages that I should consider?

Thank you very much, that's perfik. 2x47x300mm span 4.65m@C16 and 4.85m@C24 at my spacing for the higher weight dead load.

I'm hunting around for a span table that will give me some purlin size options for a 4.5m span with purlin spacing at 1.5m, and so far turning up empty. My plans say "existing" for the purlins. I have a mishmash of sizes currently and if I'm going to replace them all I may as well standardise them. The existing purlins for the 4.5m span above are 250x75mm these seem a bit on the svelt side. Anyone have a span table that covers 4.5m? TIA.

This is our stairwell edge It's this kind of detail that has me thinking about the entire edge of the stairwell.

Glue and screw everything except the trimmer edge. Cut back if required and glue and screw the edge just before installing the handrail. I like this idea. We've only looked a rough ideas for stairs. What we end up with will be heavily determined by how much budget we have left overspent All of the P5 boards will be end on to the stair opening, and connect through to the adjoining rooms. If I went with this option I'd probably be better not installing the boards just yet. Thanks for the suggestions. I'll think about them whilst fitting the noggins.

I've almost finished with the joists for our landing area and P5 is next. We have minimal detail for our stairs other than the opening size, turns etc., so have been looking around at landing construction. I'm still unsure if I should lay the P5 to the edge of the stairwell trimmer or leave a gap at the edge for landing nosing and the like?

Resin is just a convenience thing. I'm already using resin to secure wall ties, so easy to use resin for hangers when I next insert ties... I could do that for some of the joists. A few joists be sat on brickwork where there are openings above them. I'm favouring masonry hangers for the remainder at the moment. I've also considered pocketing. I could punch through from the other remaining room that doesn't have joists in place yet, and feed the joists in from there.

I've been marking out the floor level in one of our rooms and looking at where the tangs for joist hangers will sit. Almost all of the holes will be cut close to the edges of bricks, no holes are usefully close to the mortar beds. So far I've thought of four ways to cut the holes for the tangs. Grinder - messy, holes will be much wider than needed. Chain drilling and plug chisel - ok, but not the neatest of slots created. Probably break the bricks. Armeg SDS TCT brick chisel - never used one, but I expect a slightly neater hole that with the chain drilling. Again, probably break the bricks. AS160 saw with plunge blades - the best solution, but I would forfeit too many pies and beer with the purchase cost. How would you cut the slots for the hanger tangs? A secondary question. Is it ok to resin the tangs in place rather than mortar them in?

I could have, yes. Having started I decided to carry on with the boards. ?

I'm a good way through putting up my internal walls and creating a cavity against an existing outer wall and I agree with @Johnny Jekyll it's been a pain. I'm the brickie, so no problems with me re-laying blocks umpteen times, or removing deformities on the blocks to get things as straight as I can for the PIR boards, but truly a pain. Beads or injected/poured PIR if a ever get the silly idea to do this again.

@PeterW Does the green outline I drew in the picture above match what you had in mind for the optimum line?

Laying blocks on their side is 25mm off the wall width. Close enough?

Something like this? The blocks will pretty much start off at the bottom left edge of the wall and stop at , or close to the top right edge.

Hopefully wet plaster on either side of the wall. It may end up being dot n dab.

I've started to look at bricking up an internal opening this evening. Basically closing up a wide opening to doorway size. Couple of lintels to go over the doorway opening, and a tiny triangle of bricks above that to the apex. Marked a line down the centre of the existing bricks and screwed the top fixing of a crocodile in place. Let go of the crocodile after marking the lower fixing points and watched it swing away from centre. It's got quite a lean. Picture attached with a laser level on it to give an idea of the lean. Ancient existing bricks are 240mm wide. I'm planning to use dense concrete blocks on their side, so new bit will be 25mm shy of the existing width. I'm not sure what to brick to with this. Pick a side and follow the current lean? Half the lean and try to straighten out a little? Ignore the lean and go vertical? How would you do it?

First part of flooring is in place. In case it helps anyone else in a future search the hatches are like this: And to aid lid movement I chamfered the front edge of the lid:

That makes it clearer. Thank you. Started carrying the boards up the ladder to the first floor tonight. Will get to creating the first hatch soon. I'm favouring somewhere central for it. Any reasons not to have it centrally?

I was hoping that was the case and not me being rather thick and not understanding.