Big Jimbo

Do as @Nickfromwales advised. We cant tell if that wall has been built off the B and B, or off the foundations. Spend £30 and have it sorted.

In an ideal world design them out ?

I am aware that they do need to be done up very tight. That is actually quite hard to do. I have known a couple of instances where they have indeed leaked during air testing.

Nah, defo the bloke from PSB

The guy second from the right is defo the bloke who plays keyboards in the Pet Shop Boys

tell your architwat to get lost. No conditioin, NO bat survey.

I wouldn't @Erriff. Unless it is a condition of your permission.

Bad eaves detail, with a warm roof. How many times do we see that.

Yeah, @Thorfun. But our @Pocster, always gives the best laugh per post by a mile.

Nice job @FuerteStu Only my opinion, but i wish you had curved that second step. However, fab job, pat on the back.

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.