andreas

Thanks Nick, on both counts

The extractor fan I have to fit has a 150mm spigot and advises that you must not reduce to 125mm, but you can adapt to 220 x 90mm flat. I don't quite have room to run 150 round ducting, but I could relatively easily run a 220 x 90 flat duct directly through the wall. Is there any issue doing so? The only obstacle I've found so far is that I cannot find any form of external wall vent termination with backdraft flaps for that size flat ducting. I have found a 220 x 90 joiner with damper fitted internally, that would have to be placed in the hole cut in the internal leaf of the wall, then a (very) short bit of duct to the back of a standard double vent airbrick. Any issues with doing that as well? Any other suggestions?!

Thank you

We had our stopcock replaced as it was seized up. At the same time the plumber added a double check valve as they said it was required. Our incoming main is 25mm plastic but drops straight to 15mm at the stopcock. The previous stopcock was a 22 mm stopcock with reducer to 15mm, the new stopcock and valve are 15mm. Since it was changed, if someone turns on a tap whilst someone else is in the shower both flow and temperature change in the shower which didn't happen before (combi boiler). Would it be the double check valve causing a significant reduction in flow? Would it be best to replace them with 22mm stopcock and double check valve then reduce down to the 15mm be more like it was before or would that not achieve anything?

any ideas?

We blocked up an opening in an internal wall. The wall either side has cement base and plaster finish. We are going to match the depth of the cement base both sides and then skim the entire wall completely but is there anything that I need to do to "join" the new bit into the old. The plastered edge of the existing opening was knocked off before the block work was built up and wall starters used both sides to join the closure to the original either side but there is still a very straight line to the old plaster & cement base. An opening that had been originally been blocked up has a clear hairline crack around the opening, I would like to avoid the same happening here.

this is for internal leaf so would need scratch coat and plaster. Would that be an issue?

I am going to block an external doorway up. The lintel will remain above the doorway. The existing internal leaf is cinder block. Is there any disadvantage to using thermalite blocks to block the hole up? I have enough of them to do the job sat waiting to go in the skip and would have to go and buy anything else if they are unsuitable.

thank you

Thank you. any recommendations on tape? Is there any *disadvantage* to a vapour barrier other than unnecessary cost?

On a suspended wooden floor, I have to replace so many floorboards that I have decided to lift them all, insulate between the joists with PIR while they are up and refloor in P5 Caber. The airbricks are between the joists, same height as the base of the joists. Would chamfering off the end of the insulation to form an air chute be acceptable? I know it wouldn't be perfect from an insulation perspective as it would only leave 30mm thickness at the thinnest part of the chamfer but moving the air bricks is not really viable as they are only one course above outside level - moving them any lower they'll be at ground level (one would actually be below). Also wondering what the best vapour barrier would be to put between joists / insulation and caber, and anything else I should consider before I start.?

Thank you will both will look at SWA

Meter tails need to be moved but they need to be run in conduit for mechanical protection through a cavity. Due to route they will take they can't be fitted in a single conduit as it's too big to fit past a steel. Is there any reason that the individual tails couldn't each be run in 20mm conduit (which will clear obstruction) and just have 3 gland nuts either end? There is loads of room to do that and it would make it simple.

We are going to block an external doorway up. It is right in the very corner of a room. LHS of door is just a continuation of the perpendicular internal wall. It looks shite and never gets used. We are also thinking about increasing the size of the window that is beside it. There are two separate lintels at the moment, for door and window as shown in sketch. (the pillar between is only 300mm, if only they had put one lintel all the way across) If we build the doorway up in cinder block to match existing, could we just cut the existing door lintel shorter by about 300mm, remove the lintel in place above the window and rest a new lintel across, removing the pillar, or would we have to dig the lintel out the wall to the left of the door and put it all the way across? I have never blocked a door up before so I watched some videos. Some of them cut the cavity return to create a continuation of the cavity. In others they do not bother, they just build up and leave the cavity closers in place. Is there a rule on this, or any reason to do / not do it besides the obvious cold bridge? The house construction is cinder block internal and brick external, the cavity closers in this case is cinder block returns with a DPC between it and the outer skin.

Thank you, that was interesting reading and very helpful I think! A question if I may - if the cable is clipped along the joists so only has insulation on one side of it, would you then use reference method 102? I know the end result is the same I just don't want to try and argue it and not have things right in my head. Would you also have reference to where >20amps is acceptable just so I have everything to back it up?