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I am ready for first fix electrics in a very small barn/office with mezzanine bunk bed and shower room and would welcome any advice on the lighting plan. I have an electrician on board but he is currently out of action/contact with covid symptoms. S1 – switch for 24v LED strip lighting under the mezzanine bed S2 – main switch for lighting S3 – positioned at mezzanine/bed level it is a 2 gang switch – one switch as 2 way with S2 and other switch for bed reading lights S4 – switch for lighting in shower/toilet room positioned outside the room Avoiding any ceiling roses with circuit wires being brought into the switch. All wiring 1.5mm 2 core except wire from S2 to S3 in 1.5mm 3 core. Questions: Anything wrong with the layout? (especially the 2 way switch S2/S3 and then going on to S4) Could I use 1mm 2 core for all wires from switches to lamps? (most lighting would be from S2 – 4 small lamps on the purlins with overall length under 10m) Would 35mm back boxes be sufficient? 25mm? Minimum distance of wiring from EPS insulation? (only couple of sections where this is relevant)

Excellent - thanks all

I am planning on a wide stud wall (150mm?) for a concealed cistern. Is there anything in the regs to stop me having a double socket on the back of this wall in the living space? (it would be lower than the cistern and slightly to the side)

you can always shave a bigger peg down but not the other way round!

will be scraping the existing back so not simply going on top

By 20mm base coat do you mean a base coat with 20mm aggregate? Which then needs sealing (with what?) if no wear course going on. So in theory you could have just an 80mm layer so long as it is sealed. I have measured the track on google and it comes to 215 metres - width looking at 3.5m. When you say 'done properly' in your estimate peter do you include materials/work for compacted sub base, tarmac and edging (kerbs or are there other options?)?

Anyone with knowledge on tarmac? I have a 300m single track I share with neighbours and there is movement to tarmac the lot as it is a pothole nightmare despite multiple filling ins. Tractors/lorries all drive down it fairly regularly. I know there is a trade off between quality/depth of sub base and longevity but there are significant cost issues. 1. What is the minimum overall depth of tarmac anyone would suggest? 2. What size aggregate would be best? 2. How important is it to have a wearing course? Or can one get away with one layer? Presumably a wearing course has finer aggregate - 10mm? 6mm? Cheers

I believe the first course has to be layed very precisely to make the rest go smoothly. Something to think about when hiring workers and assessing their work.

What does it say on the tin?

I've used hydraulic lime bags that are well out of date and they have been fine. Never had much success with out of date bags of multi finish! Goes off much too quick.

why can't you weld them to the container?

Could I just go for a basin trap with built in AAV as I will have some issues getting an AAV behind the toilet? I think I hadn't quite clicked that an anti syphon trap is essentially an AAV.

I have a small shower room in a small outbuilding/office with waste plumbing as in the drawing. It goes to a sewage treatment plant and this is vented at the end of the run through the roof of a barn conversion about 25m upstream of the shower room/office. In the interest of the toilet not sucking water out of basin/shower traps is my best option: 1. fit anti syphon traps to both shower and basin 2. fit an AAV - if so where should it go? can it go where I indicate on the drawing or should it be closer to the toilet (upstream of the shower and basin) 3. Fit all the above. 4. Don't bother with any of them - it will all be fine!

As punter suggests - much much trickier to retrofit.

Sips should be reasonably airtight as a build method without going the extra mile . I would just plan for Mvhr from the outset and make sure it's as airtight as you can get.

I would mix up a dryish hydraulic lime/sand mortar and point that in having taken out any existing loose mortar. Finish with limewash to match existing. As Jeremy asks - do you know if the existing brick infill panels have the original lime mortar? And is the paint a limewash or a more modern paint that might not be breathable?

interesting point. I'll have to check the electric situation. I have a 16mm feed about 40m from the 3 phase d/n it is coming from. Only plugs, lights and electric heater so I guess bigger than 8.5kw might be possible.

I used some stone that came out of a floor I dug up and a render finish.

thanks everyone I think I'll go find me a triton

Anyone got any view on the different electric shower manufacturers? Going to have an 8.5kw shower in a guest space. I've used Gainsborough showers before but have had to replace main unit fairly often. Triton, Mira, Bristan.......or are they much of a muchness? Anything to look out for?

No extra cost for standing charge or per kw for my 3 phase. But there was already a 3 phase account set up on a weird tariff. Don't know if setup cost might be greater for new account than single phase. Definitely go for 3 phase if you can I reckon.

I assumed you can't put a boss on a swept bend and it is mucked in anyway so couldn't get a strap around it if I wanted to. Hence trying to work out the lowest place I can get the shower waste in above the bend.

I don't think I have the height to get the shower to floor level. The bend ifits very closely to the existing pipe/inspection chamber just outside the building so no room to drop in a boss any further down. There is no stack to speak off just the bend into the inspection chamber.

thanks temp - i'll have to have a closer look at the measurements when I get a chance. I had assumed I would need a small step up to the shower which is fine - I just want to keep it to the minimum. When slab and swept bend were put in a while ago the plan didn't include a shower. I appreciate that 50mm of insulation isn't much but it is an insulated limecrete slab already. And yes the swept bend has a female socket in the room so that helps.

I have a toilet and shower in a small downstairs room with a 110mm swept bend finishing 35mm over the top of slab. On top of slab I have 50mm insulation and 25mm tiles. Can I use a 110mm 92.5 single branch 92.5Deg 2 Boss like this with the toilet pipe into 110mm and shower waste into boss at same level? What about using one like this with the shower waste entering below the toilet waste? Is that allowed by building regs or is there too much danger of toilet waste entering the shower waste?