Conor

I wouldn't use OSB, it'll flake apart with wear. I'd use 18mm ply.

What condition are the timbers in? Is there water ingress? Looks like it's been patched up a fair bit over the years already. Id assume a potential £10-£15k job at some point in near future.

It's condensation. It takes months for a house to dry out. Keep windows open 24x7.

Can't go much higher without planning permission / annoying your neighbours. I'd plant a stand of fast growing trees tight against the wall. 6 l, 3m high trees will cost you about £1k, depending on species. Natives are cheapest, e.g. birch or rowan.

We have that in our basement. Matt black taps and shower. No issues.

I cast a 900x900mm concrete platform for our cylinder directly on top of the PIR insualtion. It needed to go in before we did the floor screed. Worked out well. Sits about 40mm higher than the finished floor and is only slightly bigger than the tank. The buffer is wall mounted.

As Gaz says, leave the old insualtion in place and lay the new stuff over. It's not worth the mess, and you're saving on materials

100mm cavity with 90mm insualtion is from the 1990s, it's not enough. Also some poor cold bridging details that will be a concern. Strange as they've got a decent 150mm.im.the floor and 400mm mineral wool in the loft. Get a full heatloss model done now before you start. You certainly don't want to scrape through the assessment, you want to fly through.

After building control signoff.

Yep, kind have to if you want the air to get out!!

As above, lift the tarmac and put down concrete or screed, depending on the thickness. Anything else will fail.

It's easy, not much more challenging than wiring a plug. I did my own.

@Nickfromwales I'm assuming he means the diameter of the plenum outlet. I used lindab airy valves with flat plates in white. work well and don't notice them. All you need them to do.

Stick a dpc and coping stone on the top and it'll bere here in a hundred years. If you don't, you'll get a decade, tops

Welcome I knew nothing when I started on this site three years ago. Now, I regularly dispense answers to questions on a daily basis. I still don't know much tho...

Get rid of the chimney entirely. Brother had similar issues, spent about £2k on various attempts. Still has issues, and always will.

Are they recommending 35mm plastic or 35mm copper? If the former then pretty much the same as 28mm copper. 28mm copper should be more than enough. Are you having flow rate issues?

Paving - reduce chance of accidental damage to the roof covering. Will also reduce sound transmission. Assume you think planning will be ok with an overlooking balcony? Some LAs despise them.

I checked and never earthed mine. Asked here as well. Not sure if it was the right or wrong thing, but too late to worry about it.

If the assessor has assumed a worst case airtightness, and you get a much better result, you may well pass. There are lots of people to blame for this, but none fully responsible. It's the embedded culture of "that'll do", "not my problem" and a system that is rigged by developers . PV is a no-brainer regardless of the air test.

Can you dig deeper? I'd be aiming for 150mm. We put in 200mm (new build tho). I'm not sure 75mm would pass BC.

Sounds like you've a blockage / restriction in your flow/return pipework to the manifold. Could be any range off issues from faulty / incorrect spec pump, blocked filter etc.

Photos? How much ponding?

Personally I would have put them in short lengths of flexible conduit. You can still do this by splitting the lengths and snapping them on.

I have this Titan 20" chainsaw that I've been using for all sorts of jobs. Chain is knackered. Dont have the time, tools or skill to try to sharpen it. I need to cut back our tall hedge - plenty of stems from 25-50mm so the hedge trimmer wont cut it. What things matter when picking a compatible chain? Is it just the bar length? Is the number of drive links specific to the machine or the chain? This cheapy seems to be the right spec, but 76 vs 78 drive links? Or this original Oregon which I think is the same as the one on it?