Hi Everyone!I need some advice on how to prevent (potential) penetrating damp on the inside of my external walls of my new house. I have been given differing advice by 3 supposed experts. I'll go in to as much detail as possible, which should hopefully help anyone with the right knowledge give a good opinion...My girlfriend and I recently purchased a house in Cornwall, England. The house itself is an old stone-built farmhouse, constructed circa 1850 and is high up on the moors where it is regularly in contact with windy and rainy weather.The house was purchased in a high state of disrepair, which is partly what attracted us to it - a DIY project / learning experience for us both. Before committing to purchase, we had a RICS Buildings Survey conducted which highlighted several problems, but at the same time relied heavily on guesswork and conjecture. However, the "findings" leave me slightly paranoid so I want to try and rectify them and minimise ongoing repairs in the future.As I mentioned, the house was in a heavily unfinished state - the walls/floors were simply plasterboard, exposed wiring everywhere, roof tiles missing... despite this, the previous owners lived in the property for around 5 years with it in this state. The property has no central heating, and the only heat source is a wood-burning stove in the living room. Incidentally, it is the living room where 2 external walls are showing damp patches.I am being forced to strip every room back to the brick, as the house requires a full electrical re-wire. I did some research on how I could best insulate the property and prevent damp in future. I found that most properties built before 1920 did not use cavity walls, and so walls in these properties needed to "breathe". The previous owner had set up the walls in the following layout: Stone > Cement Plaster(?) > Batten > Plasterboard. Based on what I had read, this setup was not letting the walls breathe. Couple that with the wood-burner providing intense heat, and it made perfect sense to me why sweaty patches may have appeared. I will attach some images of the walls (taken after I had removed the plasterboard).Wall 1 - The door is defective and the window is suffering from wet rot - both are being replaced! Wall 2 - I am not sure why the cling film was present beneath the plasterboard!I had read that traditional homes like this can benefit from lime plaster, so I called in a specialist lime plaster company to take a look. I was advised that the entire property should be coated in lime plaster outside, as well as the external walls inside. I was quoted nearly £10,000 for this. He also said the construction of the property is not original and non-breathable cement has been used. Here is an image of the brick-work. It certainly looks original to me...Next, I called in a company who specialised in preserving older properties via damp-proofing and timber treatments etc. The guy was helpful and shared my views on most of the other problems (unrelated to this long, drawn-out question). For the problem walls, he suggested fitting a cavity drainage membrane and then fixing insulated plasterboard via dot-and-dab method. This made sense to me, but the price of £3000 did not. I can get these materials for £400 or less with a quick Google search.My question - finally - is: would you recommend installing a cavity membrane and then insulated (breathable?) plasterboard on top of that, before plastering/skimming/painting? If so, is there anything stopping me doing this myself, or is the expertise of a professional really worth £3000 when I can probably do it for £1000? Or maybe I don't need any membrane at all, and simply using something like this directly on to batten would be sufficient? I worry that this may trap/hide the damp, and not stop the problem.Thanks for taking the time to read - I appreciate all your thoughts! via /r/DIY https://ift.tt/2wfVBT2
