jayc89

Nice, that'd work quite well. What size attenuators are those, no problem with sound transfer? I was thinking 600mm for supply and 300mm for extract (for rooms where noise transfer is less of a concern) How did you secure the distribution boxes to the wall like that? Awesome, thanks. Any problems with the tight bends? I was thinking of using 2x 45 degree bends, or a long sweeping 90. More out of caution than any solid reasoning!

Currently trying to picture my MVHR install. Right hand unit to be wall mounted in the loft, all room ducts come up through the loft boards, 2x 10x port distribution boxes to be mounted next to the unit (somewhere), in theory the boxes could be below the loft boards, but it would need additional joints and would make them inaccessible. I'm thinking of having them all wall mounted serially and use spiral ducting, attenuators (thinking spiral attenuators vs the flexible ones) and multiple 45 degree elbows to make the connections. Does anyone have anything similar I can see some pictures of?

They wanted £60 for it! Luckily, the old unit was sitting on the original bracket.

Possibly a dumb question, it's been a long day. Section of loft already has some insulation; 75mm between ceiling joists and then 100mm over. I'd like to add another 200mm, but how do I lay it without compressing the existing 100mm? I'd rather lay it over existing than remove the existing 100mm and run new across the ceiling joists.

Both!

I picked up a Pi4 thinking I'd use it to log data from the house. I was particularly interested in when the heating turned on and for how long (I suspect it short cycles when only one zone calls for heat). Haven't got around to even turning it on yet.

I picked up a second hand Brink Flair 325 unit, it didn't come with the wall mount, which I'd like. I can't seem to find any online at any of the normal retailers, any ideas where I can pick one up from?

I thought there should be a gap between the insulation and the PB?

That's a lot of loops. What's the total volume of water flowing through them?

Presumably the compression behind that big washer (ledger) is great, and would be transferred to anything between it and the wall (insulation), so something like PIR would just get crushed by it? (Hence needing something specialised like Compacfoam)

Osma seem to do two different products; Osma Weld and Osma Waste Solvent Weld. https://www.travisperkins.co.uk/solvent-weld-waste-pipe/osma-waste-solvent-weld-waste-system-white-knuckle-bend-50mm/p/818158 https://www.travisperkins.co.uk/solvent-weld-waste-pipe/osmaweld-90-knuckle-bend-white-50mm/p/173119 One's made with PVC, the other ABS. I can't see any other difference though, is there any? Can they be used interchangeably?

I have a solid wall construction and I'm packing the gaps and brickwork in the void with lime mortar.

This is the sort of thing I was thinking; All internal plumbing is new, which I'd prefer to do in solvent weld, the SVP already exists and is push fit. I could probably run the single shower run in 40mm, but I'd have plenty of 50mm pipe left over, so why not!?

Third question - is 100mm solvent weld "a thing"? My BM is struggling to get hold of any, my plan was to have my bath/shower/basin drains all connect into the 110mm pipe using branches and reducers. I'm assuming 110mm solvent weld pipe is like 32/40/50mm pipe and differently sized to 110mm push fit pipe, so mixing the two wouldn't work? (I'd prefer solvent weld everywhere internally and somehow converting to push fit externally)

I'm replacing a small-ish section of first floor joists with posi-joists (4.5m x 3.8m), I'm wondering whether I should insulate behind the ledger board before hand, but appreciate the calcs for doing so aren't simple. I came across a Green Building Store blog where they did something similar using Compacfoam 200; I'd have thought the point loads in that set up would be quite high, opposed to running a strip the full length of the ledger board and 1.5x the height to distribute the load across the full wall. But, Compacfoam 200 looks to have 10x the compressive strength to EPS 300, which is pretty impressive, and probably explains how they were capable of using it like that. How would you calculate the compressive strength required of any insulation fitted behind a ledger board?

Never used LA, using a private firm right now and they've been spot on so far.

What's the reason behind that?

THISTLE MultiFinish Plaster ................ Nominal Bag Weight 25.0kg 7.69 EA But that was in July so might have changed since?

I just paid; KNAUF MOISTURE PANEL 15MM TE 1200 X 2400 13.45 KNAUF PLASTERBOARD/WALLBOARD 2400X1200X15.0MM SQUARE EDGE 9.49 Pretty chuffed with the contact I have at the BM. Our order value probably averages £2-3k each but I'm sure they have far bigger customers than me!

Agreed, but I thought 8mm or span x 0.002 is typically recommended around here, not whatever LABC would accept (which I assume is what the span tables work to). That being said, the solid joists I'm looking at have a max span of 3.946m at 600 centres, or 4.512 at 400 centres, so my span of 3.8m at 400 centres should be well within that tolerance?

Some American calculator suggests the solid joist deflection would be around 6mm. Although there was a lot of conversion between mm and inches to get that.

Posi joists were designed for under 8mm deflection. Solid joists were designed (by me) using the LABC table, picking the joist size suitable for the span at 600 centres and I'd fit them at 400 centres. How can I calculate the deflection of the solid joists myself?

Not sure I was meant to be tagged in this one 🤣

I need to fit new floor joists into a room which will become our ensuite. The old ones aren't suitable to support a bath and they're in the wrong direction to route the soil pipe. The room's 4.3m x 3.8m. I have two options; - 3.8m 97 × 202 posi joists secured to 4.3m ledger board. These will allow me to run the soil pipe through the webs and straight out the perimeter wall. Is more expensive and will take longer to be delivered. - 4.3m 72 × 220 solid timber joists secured to 3.8m ledger board. Would need to rotate the joists 90 degrees so I can run the soil pipe parallel to them, which means they'd have a longer span and I'd need to core through the ledger board (and wall behind) for the soil pipe to exit. I can get these delivered this week, to be fitted over the weekend. Given a 72 × 220 ledger board, could I cut a 110mm hole through it? Or could I effectively fit 2x ledger boards to the wall, with a gap where the soil pipe will exit the wall?

Secondary question, do I need any sort of AAV to the left of Ensuite #1, or is the vent on top of the external SVP enough? (The vent is already higher than any new W/C I'll be fitting)