Roger440

For what its worth, he surveyed my house prior to purchase. Identified lots of issues. Everything he saw, which couldnt be further established without destructive work turned out to be pretty much bob on. Ive found nothing of note that he didnt pick up. Expensive. Very. Useful and worth it. Definitely.

If you can be sure the dpc is fixed/working, then all should be well, but id still tread carefully. My house is similar, old bit half the size of the new bit, though i didnt build it. I just accept that the downstairs part of the original house just wont be that good. Ie, no insulation on the walls, but will have in the floor (foamed glass) My old 30's semi cost twice as much to heat as this, and this is twice the size. Thats despite having the flue from the wood burner (now removed) open, But it has to be or the humidity starts to climb. Basically its viable top close off the ventilation without creating other issues. I suppose i could use MHVR. But as its comfortable, and not that expensive to heat, i'll live with it.

There has been a flurry of posts on here about older houses. Stop, and get educated on it first. Insulated plaster board, celotex etc. No, no no. Not in an 1800;s house. Seriously, peruse, at length, these 4 sites before you do work you later find needs ripping out. One word. Breathability. https://www.heritage-house.org/ https://www.mikewye.co.uk/ https://www.lime.org.uk/ https://www.periodproperty.co.uk/forum/viewforum.php?f=1

Yes, everything temp said yesterday. Its a nightmare. Simply no containers available. Currently you need to pay 8-10 times the ore october rates IF you can get one. If your products are bulky releative to cost, prices are going to be going up big time. Ask me how i know...................................... Worldwide trade is coming to a standstill. Not going to be pretty.

These guys seem pretty good. And significantly cheaper than the likes of watco. Been using their floor paint. Seems top quality. (ive used a few............) https://fixmaster.co.uk/categories/repair-products

It still wont soak the entire brick. Its impossible. It cant work. Unless you house is built of sponges! My house has had it done. Line off tell tale holes around the base of wall. Had zero effect. Walls are damp, inevitably. Gypsum plater inside, concrete floor with DPM undr, render painted with modern plastic paint. The perfect recipe for damp. As it happens, we removed the plaster today. Sockets are 400mm up the wall. The steel back boxes are terminally rusty. The srcews holding the rads on, terminaly rusty. Chemical DPC not doing whats its claimed, thats one certainty.

Unless you can "fix" the DPC properly, it needs to dissipate the moisture through whatever is on the wall both sides. Ie, breathable. And dont let the drivel on modern coatings that claim to be breathable fool you. There is a measure for the breathability. Compare that number to actual lime based poducts and you will see the issue. That said, just talk to the lime guys and be guided by them.

Thats what im using for the floor in the old part of the cottage.

Yes, this website^^^^. And read all of it.

420 is rather a lot. Solutions aside, thats the water table now. Id suggest that at times it will be higher.

You could look at it another way. And some evidence it actually works? Think about it. A man will drill some holes in you wall and inject "something". This something needs to permeate through the bricks and mortar to such an extent that they form a barrier impervioius to water. Its simply not credible. Get a brick drop it in a bucket of water for a week, then cut it in half. I bet you its dry in the middle. Thats a week in water. But a bloke with a mastic gun is going to squirt something into you brick to make it completely waterproof in a few hours. Doesnt look like the damp comes up far enough to be a problem?

OOh, and a chemical DPC us just a scam, as already pointed out. Dont waste your time or money.

Once you have read the heritage house website, you will, hopefully realise, that with a compromised DPC, you are not fixing your damp issue, merely covering it up. With a DPC on the inside, and EWI on the outside, your wall will be wet forever. As one of the videos says, if you wash your clothes, put them in a plastic bag, and hang them on the washing line, what do you think will happen. This is, effectively, what your proposal does. Either you need to fix the dpc properly, or treat the building as though it doesnt have one. The fact the floor was rotten says you have a problem with moisture, Dumping a load of concrete in there wont fix it. You need to understand the reason why first and work from there.

Our posts overlapped. Not much point using sheepswool if you slap plasterboard over it. Plasterboard will prevent moisture leaving the wall. If you are allowing breathability, it has to be every layer, including the paint. One "waterproof" layer will render your efforts worthless.

Given its age i would tread very carefully. It wont have a damp proof course, so the walls and floor will need to breathe or they will get wet (probably are now.) Most insulation systems will prevent that from taking place, storing up future trouble. Id suggest a peruse here would be a good idea. https://www.lime.org.uk/ Im just about to use their sublime insulated floor system. Periodproperty forum is good too, though some of them can be a bit harrdcore!