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About MarkyP

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  1. MarkyP

    sound proofing - joist foam strips

    I had looked at this, I guess the joist strips with floating timber deck is a cheap version of the same. I was thinking of getting the impact noise benefit without the cost and hassle of the full system. It's temporary storage of building materials, will be an occupied upper floor when done.
  2. MarkyP

    sound proofing - joist foam strips

    I thought upstairs was going to be carpeted, but seems the Mrs thought wood, hence my worry about impact noise. regupol looks interesting, seems you can bond that to the chipboard, and then bond an engineered floor over that.
  3. I'm almost ready to lay a chipboard floor in my loft conversion. I've been thinking about the issue of sound transmission. I've tightly placed 150mm of rockwool RWA45 between the (220mm) joists which is already far more sound insulation than any other house I've ever owned but I'm having one last look at options before I put the chipboard down. (The option of adding resilient bars and double layer of PB below just would have been too disruptive, it's a large bungalow and would have been 5 rooms' worth of ceilings to take down and replace. however, I recently saw a system which uses a dense foam strip over the top of each joist, and then the chipboard laid atop this but floating rather than nail or screw fixed. I'm assuming this is helpful in reducing impact noise through the joist structure. Does anyone have any experience with this solution? I have loose laid some of the chipboard floor to create a temporary storage deck and it sits nicely on the joists with no bounce or rocking so wondering if actually it might be easy enough to float the 22mm deck, gluing the T&G sheets but not screwing into the joists, leaving this 10mm dense foam pad to absorb some impact noise. The joists are at 600 centres so one concern is that heavy furniture in one area might cause some flex in the chipboard between joists, lifting it elsewhere due to the absence of screws.
  4. MarkyP

    Internal blockwork walls

    Our block layers hated thermalites and were much happier when I specified medium density. Thermalites are much more prone to cracking than medium density, especially around openings and reveals. And they are ridiculously absorbent and I think this makes them hard to lay, within a few minutes of laying a mortar bed along a course it's started to stiffen before you've had a chance to lay the blocks on top. You have to pirme the edges of the blocks with water as you go to try and control the suction. And in warm weather the water can be pulled out of the mortar bed very rapidly, before it's had time to cure properly. Also, they are a beast to wet plaster, requiring copious priming with PVA to kill the suction. As above, medium density are going to create a better sound barrier and are much nicer to fix to. The only one who grumbles about medium density is the poor labourer who has to haul them up the scaffold all day! I'd use them everywhere, a small increment to insulation layer will offset any lost thermal performance.
  5. and the other question is whether you should be paying for it at all if the builder has quoted for the work and is working to a set of detailed design drawings. The question I guess is why this add on has become necessary.
  6. assuming there aren't hidden complexities here (and that this per an engineer's design) I would get a quote for supply of the steel plate - try a local fabricator or two and also a regional stockholder ( I used Parkers and they were cheap and price was very negotiable). Then get a hourly rate for site work from a local welder, and an estimate of the hours. Then you can have a chat with you builder and ask if he's mistakenly added a "1" in front of the price 🙂
  7. MarkyP

    DPM above or below concrete slab

    typical build up would be hardcore, 25mm sand blinding layer (to protect DPM from being punctured when concrete is poured), DPM/Radon barrier, concrete slab, insulation, polythene separating layer (500 gauge poly), UFH pipe worked clipped, screed. the polythene separating layer over the insulation isn't really as a DPM, it typically serves to protect the insulation from contact with the wet screed. I believe this is because the foil facing of PIR reacts with wet cement. It is also, where a liquid pumped screed is used, to create a bath to hold the screed and stop it running down the sides or between the insulation sheets before it sets. Some have used a further DPM over the slab where there is concern it hasn't dried fully.
  8. is it too late to consider wet plastering? It's a parge and finish in one. Also even well pointed blockwork is still going to have hairline gaps in places in the joints. If you have to dot and dab I would use a parge coat. Prime the blockwork with PVA solution first, it's a nightmare trying to soak thermalites as they will take an amazing amount of water. Sand and cement wet slurry with fibres or even a thin skim of bonding or hardwall would do as a parge I think. But even with a parge, if (when) the blockwork cracks then you'll get a potential air leak behind the boards. with wet plaster, any cracks that do appear can be seen and addressed. You'll never know what's going on behind the dabbed boards.
  9. MarkyP

    What type of boarding above rafters

    yes this why I said I will need to double check choice of tape. If the tape isn't sufficiently vapour open then this would indeed will be a waste of time. My aim is to improve the vapour permeability of the OSB with a series of air tight but vapour open holes.
  10. MarkyP

    how to patch up a 2cm line of plaster?

    personally I wouldn't but there's more than one way to skin this cat. The tape will adhere to plaster in my experience. But you will have to skim over the tape, and then feather out into the body of the existing plaster which some might find a fiddle as you have to cover the tape suffuciently to avoid it grinning through. this is why dry lining boards have tapered edges, to ensure the tape sits below the finished surface. If you chip back the existing plaster you can tape in the recess and then fill flush to the old plaster. Chipping back cleanly can be fiddly. And you will still have a joint between the old skim and filler. This wont be as crack prone but still might hairline crack with doors opening and closing. edit to add that the latter will be easier to get a clean finish if you haven't done much of this sort of thing before.
  11. MarkyP

    What type of boarding above rafters

    I have OSB 3 sarking, as designed the intent was to full fill with mineral wool between 170mm deep rafters and then 70mm PIR below. This was passed at bc subsmission stage but since on site BCO has questioned condensation risk on the inside of the OSB. A VCL would if perfectly fitted address this from a CRA point of view but there is a tricky detail at eaves (this section is of the building is retrofit) and around dwarf wall uprights in the trusses which will be a fiddle to detail the VCL perfectly so perhaps not unreasonable of BCO to question whether I will 100% prevent vapour (or even air) moving from warm side into the build up. So my plan, while it will be a chore, is to drill two rows of 8mm holes @ 200mm centres through the OSB in each rafter bay and then run a strip of air tightness tape over each row to prevent wind washing of my insulation once fitted as the OSB was all carefully taped to be wind tight. Above the OSB is a ventilated counter batten void, breather, then batten/slate. I need to double check the tape of choice to ensure sufficiently vapour permeable. Have yet to discuss with BC but think this will address concerns.
  12. MarkyP

    how to patch up a 2cm line of plaster?

    if you are patching over an underlying joint between your new plasteboard and the existing skimmed walls (which it sounds like you are) then I would use plastering scrim tape over the joint before filling. Plasterboard jointing compound (used to fill joints in dry lining) is relatively forgiving stuff to use and is very easy to sand. You'll need a couple of coats, first one to get a skim over the tape, and a second to feather in, then a light sand to smooth any blemishes. You can get tubs of ready mixed jointing compound from most builders merchants and more trade focused sheds. I find it easier to prime existing plaster (unless already painted) with weak PVA solution first (leave to dry) as the joint compound stays live longer and is easier to feather out with a trowel. if you need to finish sand use very fine grade paper or you will get visible swirls when you paint. don't confuse with ready mix patching plaster products. This stuff is often grey colour and is handy for some jobs but is hard to sand, often dries a bit harder than the original skim so you can struggle to sand back and get a clean joint.
  13. I've got a bosch blue sliding mitre saw. From memory about 350 quid new. It's great and as others have said, you find all sorts of uses. For stud work I used a cordless skill saw in the main for reasons of speed but for anything requiring a precision cut, or lots of angle cuts, then mitre saw really comes into its own. I used mine yesterday to create a precision perfect mitre joint in 2.6m long window board which was made from two pieces of MDF, it's painted and you have to look really, really hard to see the joint, would have been impossible without the mitre. Architrave and skirting is made so much easier with a mitre saw, as well. I bought a quality saw expecting that I'd sell it on after the build but actually we're now planning a DIY built timber framed outbuilding, and even after than I just expect I'll keep it because it's so handy and makes such good cuts. I'd say get yourself one, there's nothing like a shiny new tool to lift your spirits on a cold winter's morning. 😉
  14. I noticed you didn't get a response so thought I'd share some thoughts.. what is the sarking made of? If it's lengths of timber with small gaps between each strip then there ought not to be a need to ventilate as it will be vapour open (with your breather and slates above) so the condensation risk on the underside of the sarking would be low, or any that did form could evaporate away readily when conditions suited. If the sarking is sheet material, like ply or OSB, then this is less breathable and the standard approach would be a ventilated void to mitigate perceived risk of condensation forming on the underside of the sarking. However, there are multiple examples of builds which have eschewed this common thinking and fully filled under OSB sarking ( using spray foam, blown cellulose or mineral wool) with vapour control to the warm side. In your case, I don't understand what the 10mm void is doing. Perhaps PIR boards are easier to source in 150mm rather than 160mm? Or perhaps this is just a fitting allowance - you mention an old house, are the rafter voids all universally 160mm deep? Again, if the sarking is strips of wood with lots of nice breather gaps, then I don't think the void is an issue. You could use a warm side VCL as an additional measure for peace of mind (just taping the foil face PIR under rafter would do, I think) I can't comment on the questions about the differences between the sheet in insulation types.
  15. MarkyP

    Thinking about buying a digger

    I've found a small dealer locally with 3 x 2.5t kubota machines. KX61-3 and UR25-3. These seem pretty well regarded so going to go and have a look. Also, by bizarre coincidence, a bloke knocked on the door recently who it turns out grew up in our place (well, in the timber shed we demolished). He was passing and just wanted to have a look around. It was then 50 years back a full blown small holding and was very interesting to learn about the history of the plot. And it turns out he's a semi-retired machine operator and he gave me a load of contacts including a local plant engineer who will for a small fee come and inspect any machine I am thinking of buying, which was nice.