Big Jimbo

One of the reasons why i hate those slopes when i see them in any property. You are going to have to try and get some insulation in there, while maintaining airflow under the tiles if you have a cold roof.

I thought that was my Mrs for a minute @Pocster. Then i realised that the lack of stocking tops ment it could not be her....... In my dreams.

Well @marshian. I am putting you on the "Proper decent job" list with that lagging alone fella.

No.wasting your time IMO. If you have a draft in the void, and a warm roof above.......You have a badly built extension. certainly a badly built roof. Do some measurements and find out if you have a warm roof.

A knackered, stuck shut motorised valve ? That would be my guess.

If the void is drafty, then the top roof, even if it is a warm roof is not doing anything ! The first thing to do ia as @Mr Punter said. Take some measurements, and establish if you have a warm roof. If you have then it will be the usual, (seen it many times) the insulation will not have been carried up to the top roof level. So many builders dont seem to have a clue how to build a warm flat roof. If you have a warm roof with a decent depth of insulation above that boarding, you would be better off ripping the ceiling down. Pir between all the joist ends. Foam the pir in with some decent air tight foam, (Not the crap you but in the sheds) You do have to get all around the outside walls, so if you find a joist close to the wall, come back to us. to get to these areas, you may need to remove the facia boards. Sorry for the bad news. no easy way to sort now. You, or the previous owners have been "Rubbish Buildered) i suspect.

Does the door frame lap into the insulated cavity by a minimum of 30mm ? If not, and it don't. then welcome to a nice thermal bridge, and a fail of building regulations.

I'm with @Conor. These days you need to think about your comfort, and your bills. Best of luck, whatever you decide.

What @Nestor is saying above is frankly, going to take you a lifetime. Belt sanders can be bought cheaply, and the use of them can be mastered in 10 minutes. Due to the age of the property, i expect that underneath the floorboards is ventilated. The biggest issue will be that a lot of your expensive heat is going to be going through all the small holes between your floorboard, and will be washed away under your house. It's a nice idea, but i think you might be dissapointed in the end. Not about the boards, but about the cold.

Yes. I think i will do different bricks, and perhaps different coloured windows. I quite fancy doing One in White glazed bricks.

Thats advertising for you @SteamyTea. Plug this tiny, (size of a fag packet) in, and it will heat up your whole house in 5 mins. As a bonus, it only costs 10 pence a day to run. A few fake reviews on Face, or instashite, and suddenly you have sold several hundred thousand of the things at £20 quid a pop. If it's on Faceshite, then it must be true.

@jack I agree with you. That looks like a right mess. I have no training, but i have done a few EPDM roofs. Some quite complicated. The oldest must be about 12 years old now. I have never had a leak.

For the cost, perhaps chuck another dpm before the pir.

If it is a rainwater system, then you can connect with permission. If you want to go into the foul system, then expect resistance from the water authority.

The PIR, when taped, will act like a vapour barrier anyway. So you are defo overthinking.

Batten on the side wall and Two part velcro. Easy on and off. Either that or magnet catches. Both available from screwfix i believe.

The external motors from "Best or Westin" that i used to use were expensive at the time. What ever you do, make sure you have a grease filter at the start, source. Try and keep bends to a minimum. Every bend with have a big effect on the airflow. If you can try and keep your pipework round. Again for the benefit of airflow. If using round pipe, try and get One that has a smooth inside. Again air does noy like going passed loads of ripples. Best of luck with the project.

You should have tipped it into his air vent @Kelvin. Nice one fella.

4 small blobs of silicon. Dont go mad, just incase it ever has to come off.

To be honest @Nickfromwales, I told the surveyor to not even bother quoting for a new supply. I was that Peed off. The only actual quote i received was £2k for the split of the existing 3phase. 100amp for each property will be fine, even if i chuck a bit of solar on each house.

@JohnMo Good questiions. Sounds like The firm building the house will simply be the main contractor. But i agree, it is confusing ? I will try and put my own situation, which sounds similar. I Own the land. I have a building company. Limited. It is dormant but i file returns. I instruct my building company to build the house, and i pay it, each time it issues me with an invoice. The company, builds the house, Zero rating my invoices as applicable. The company reclaims any Vat paid, every quarter as applicable. At the end the company shows a small profit, and deals with that as its own entity. I get the benefit of effectively not having to wait until the end to get my VAT back as a self builder. The above is my intention...

@Nickfromwales No mention of the transformer. Traffic lights, blah, blah, blah, Seems a joke at £24k. The cable is at most 750mm deep. I would have paid £5k for the future proofing of Two 3phase supplies, but, £24k buys a few materials for the build.

I don't know, but could you instruct the Limited Company to build the house on your behalf ? The limited company buys all materials, and labour, and reclaims any Vat paid, every quarter, while billing you, Zero rated as applicable. Effectively, You have a main contractor building the house for you ? The company does not own the land, or the house. You do ?

@jonny I know what you mean about cost. I have 3phase to my existing bungalow. Only One phase is metered. I have permission for knocking the bungalow, and building Two new houses. I enquired about bringing in a new 3phase supply. It is in the ditch outside the front boundary, and no more than 1.5 meters from my boundary. To bring a new supply, to a new cabinet just inside my boundary, i was quoted £24k. That was with me supplying the box at the boundary. My alternative is having the existing supply split, with each new property having 100amp single phase supply, leaving the Third phase unused. Cost £2k. Each new house is going to have a single phase. Im not paying £24k. Blinking ek.

That looks rough as IMO. A thin layer of EPS before you put the membrane down would do the job.