Cpd

I would have thought that if the walls are out of the ground, are lime pointed on the outside and in fairly good shape AND you have a ventilation gap on the inside it would not need tanking, tanking lime walls on the inside could lead to a whole lot of problems as they will no longer be able to breath properly. If you are not having a ventilation gap then the build up would normally be a specialised build up that allowed them to breath to the inside, including such things as lime based paints etc. Unless your a purist and as you already have limited space I can’t see you going down this road. I think you may need to visit one of the specialist websites, historic Scotland or the lime mortar association as tanking really does sound wrong to me........

Looks great, I painted my cabin with Cuprinol so that when it does start to look even slightly tatty I just slap on another coat of paint and it looks as good as new !

given I have a traditional 10x5m one and a half story cottage with NO option to lay pipes in a screed (as talked about before) and a desire to run an ASHP for DHW and space heating in a bid to reduce my Electricity bills and having been pointed at the WUNDA overfloor system in the past....... (can’t find the panic button) given the small nature of the cottage, the fact that it is well insulated and very air tight with MVHR and will be occupied by holiday geusts every day of the summer (6 months) and by my lot in the winter (as I upgrade my own house next door) would you recommend that I drop the idea of an over floor system and start to look at radiators specifically designed to run from an ASHP ? I would have NO problem with the visual impact of radiators as the whole “decor” is to be very quirky and rustic...... I was part way through using JSH spreadsheet to provide more heating requirements but can’t load it on this iPad, but will get specifics before moving this forward, BUT I would welcome your opinions on over floor v radiators with the broad variables at this stage. Thanks

That’s what I intend to do, cut me a bunch of holes, new membrane over the lot and put the tin back on.

Thanks for the explanation ? I will be replacing my failed membrane this summer.

That’s a worry I think..... if this was the result after several attempts of bogging up gaps and cracks it could mean some seriously poor workmanship, especially in regards to the installation of the insulation. The mvhr could well be sucking in lots of cold air from these gaps and therefore rapidly cooling the house.

Can you put a link to this product ? Not sure what the W1 part relates to. Thanks

Hello and welcome, looks like a great project my cottage looked a bit like this when I ripped it all apart........ My downstairs wall build up will be 700mm stone wall with rubble in the middle Ventilation gap between old wall and studwork 20-70mm 50mm studwork attached to wall and infilled with pir 70mm pir over front of stud work Possible service void but I’m thinking of running cables in conduit on the surface (barn style !) 12mm OSB it’s a small cottage 10x5 the additional osb layer is to allow me to fix anything anywhere ! 12mm plasterboard skim 

I went with 170mm between rafters and 25mm over the top.... am still tempted to add another 25mm or more onto the top......

I have found gyprock drywall screws to be the cheapest when buying at 90mm £14.40 for 250 quality screws for sure.

Did you foam this in > off course you did. Marking top and bottom of the joists is essential, I then line the laser line at it to get bang on centre every time....... I am sticking 60mm under my joists in the shed so it’s a bit easier, I can only buy 100mm max length drywall screws locally.

Sorry but I am a bit lost here, (happens quirte a lot...) if you drill a row of holes through the osb and then tape over them with air tight tape....... won’t that be a complete waste of time as you have just sealed it back up again........ sure I am just reading this wrong..... I am in a similar dilemma as I build my shed roof out of floor grade ply........ what a baboon I was to move away from traditional 22x150mm white wood sarking.... I was pretty ill at the time and was not in full control of this part of the project .... it’s still my fault but hay ho. I now have a surface that is not nearly breathable enough and am getting condensation build up and black mould. My plan is to take the tin off and the breather membrane that was damaged in the frost and cut some big old holes along the length of the roof top and bottom through the ply and then put new membrane on and re tin........ it was a stupid mistake..... but I was only functioning at about 20% on a good day when it was going on......

I am insulating my old stone cottage and am happy to sacrifice space for insulation. Exactly how big is your barn ? My width after framing out and insulation / final finishes will only be 4540mm the walls upstairs will be : stonework 700mm vented void 20-50mm 50mmx50mm framing attached to wall (lots of work) filled with 50mm calotex and fully sealed and taped. 25mm cross battens and infield with insulation 70mm calotex stuck on and fully sealed (vcl) 12mm osb glued and screwed through to cross battens where needed. plasterboard as @ProDave says it’s all down to detailing and I would not trust anyone except myself and my most trusted helpers my gables are even more insulated and roof even more again...... everything is detailed to the mm.

If you built a timber / metal frame within the stone walls as @Russell griffiths states and used pir and created a vcl on the warm side, could you then leave a vented void between the stone work and the insulation ? I am not sure how this would effective the risk of inter terrestrial condensation but I’m sure this Could be modelled with the right software. If you did away with a service void and ran your services “retro....” you would eliminate the “plasterboard tent” @ProDave says is such a common occurrence and should (heaven forbid) there be any gaps. They could then be Identified easily and quickly sealed up. I have an uneven gable wall that I need to deal with, it’s 1m thick (stone, rubble, stone) and my intention was to put up 25mm-50mm Celotex against the wall fully sealed, then a studwork wall against this filled with more calotex and sealed and then 25-50mm on the inside covering the whole wall. This would then have plasterboard attached directly to it with foam. If there was any condensation it would be on the stonework and as this is a vented void and it “SHOULD” dry out ........the dangerous part of this is the word “SHOULD”........ and I need to eliminate this to “WILL”

Seems crazzy expensive ! I will be renting my cottage out in the summer (what year I don’t know.....) and I know most of my guests like to have a holiday fry up when they are staying. I have wasted so much time going back and forth with what to do ! I don’t want gunk in my ducts and a mixture of dust and fat sounds like a disaster waiting to happen. I was planning on recirculating with an OVER SIZE hood to try and catch as much as possible but there is no way I would have a spare 3k...... maybe I need to pipe in a direct to outside extraction and use that until I can afford a recirculating hood..... but 3k...... impossible.

That’s correct, it’s been done like this for a very long time, I think they used to use some sort of lanolin mixture..... I just use whatever I can find but floor paint is great !

In hindsight I should have knocked the cottage down and started from scratch but hay ho..... what I have had to do is pretty much build a timber frame on the inside to support insulation and plasterboard. It’s going to work and work as well as it can but at a huge time cost. I do have a nice traditional looking 700mm-1000mm thick stone rain screen on the outside........

I have done my cottage with PIR on the inside and having worked with it a lot I am personally persuaded that unless it’s done with a great deal of care the end results are going to be poor. It’s just so easy for cold air to get in and around the wrong sides of the cut insulation, and on windy days I think your going to see even greater losses due to wind wash. On any of my insulation build ups I starter with 50mm asthis is easy to cut, easy to fit and most importantly easy to foam up and BE sure it’s propperly done. I then cut back the foam and re do anything that has a gap or dubiously big air holes in the foam. Cut back again and tape all the joints. I then add the next layer of say 100mm with the knowledge that no cold air will be getting in and around this layer, again this will be foamed and taped to the enth degree as this will also be my vcl in most cases. Again I am then sure that no warm air is going to be getting into any of the gaps. I know this does not answer your question but I just can’t see pir as a safe way to insulate without a huge amount of care and attention and a LOT of money on foam and tape. I have used an insane amount of tape and foam over that last few years........

Looks great man !

So from the top down..... Final floor not laid yet.... 22mm chipboard glued and screwed and compressed onto “no squeaks” silicon on top of each floor joist 50mm void 50mm acoustic rock wool roll 100mm RWA45 50mm rockwool vcl 12.5mm standard plasterboard 12.5mm sound block plasterboard x 2 layers...... 25mm void and battens 10mm tonge and groove cladding all layers sealed with acoustic mastic round every joint........ the reason for x3 layers of plaster board was one of my volunteers picked up the wrong stuff and we had already got the first layer up before spotting this. I always wanted two layers of soundblock so I just got on and put them up as well...... needless to say the additional ceiling build up has now caused us some loss of head room and this is dictating the floor build up..... but that’s a long way off still. This is is a tiny traditional cottage so low ceilings are not really a problem, still going to be over 2.2m just....... i still have a gaping hole where the stairs used to be so I can’t test the effects of this build up yet, but one would hope it does the job. I should have used a special de coupling system for at least one of the layers of plaster board but it was all done when I was still living in the dark ages...... ebuild and then Buildhub enabled me to drag myself into the light. everydays a school day

That’s how I did it. But DONT fo what I did..... being a tight bar steward I emptied the bag to reuse it...... it burst half filled and in the huge dust cloud I ran over the power cable.......

Just ordered this one....... will wait and see what it’s like. I need it to drill through 22-25mm thick oak (old whisky barrels) as I have a new project in development but will post a separate thread on it in a few days. It will be used in the pillar drill.

......I have also had this problem in the past but it was from a bath / shower pipe. The pipe sagged and water must have been sitting in it and the bio jelly had virtually filled the whole pipe from the bath to the main waste pipe about 2.5m ...... what a horrible experience. It takes a lot to gross me out but that was one experience I am not looking forward to repeating. I wonder how wide spread this problem is and what one does to avoid it beyond just using a lot of bleach.

I would agree, used the chipboard flooring and ply flooring sheets in two different projects and much prefer the chipboard.

Just making a staircase for my shed, made out of salvaged 10x2 for the stringers (back of the stack at builders merchant) and oak whisky barrel lids for the treads (also free) , will be 6 steps @200mm risers then a small platform and another 4 steps @200mm. It’s only 600mm wide and goes up to a walkway between two mezzanine storage areas. Should be installing them tomorrow or the day after. Cost £0 (but I did wear out a set of planer blades cleaning up the barrel lids..... time spent building it...... two days...... maybe three. But it was a great training exercise for when I have to build new stairs for the cottage.