MarkyP

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About MarkyP

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  1. And I'd love too see a new sister show of GD, it would be called Shit Designs and be a fly on the wall doc of a large volume house builder and show just how rubbish most new built stock is.
  2. I enjoyed it. I agree much better than some of the more lavish GD output. The woman was a tad irritating, I suspect there may have been an almighty bust up with the other couple off camera. My wife didnt like her because she constantly had her eyes shut when talking to camera! But showed I think that self build is within the grasp of mere mortals with more modest budgets. And the woman clearly had to cash in every asset to fund the overspend, shows the harsh reality of self build budget, rather than the usual GD wealthy professional couple giving the money tree a shake or finding an extra 250k behind the sofa. The structural issue she encountered was horrid, I really felt for her there, that gap in the ridge looked awful but I guess could have been worse - those rafters were seated by a wafer, imagine if they'd completely separated! Would have been good to have understood the root cause of that - was it design, the beams not meeting spec or installation error? . Perhaps at time of filming liability was in dispute so they had to gloss over it.
  3. I have an 18m run along a wall with EPS EWI and Baumit star contact white (cement/lime hybrid) base coat finished with silicate mineralic thin coat (nanopor fine, 1mm grit). No movement joints and no cracks and this is with multiple thin sections of render over window reveals which are often where cracks will appear. Choose carefully the finish, acrylic and some silicone thin coat looks cheap in my view, has a plastic sheen nature to it. Silicate thin coat is mineralic and looks far better in my opinion, also could be mineral painted later in life to refresh or change colour while retaining the flat, mineral finish. I was very impressed with Baumit products and technical support. I asked Baumit about expansion gaps and were told none were required. You'd need to follow the recommendations of whoever manufactures your render but the logic Baumit gave me was that they only place expansion gaps where there is a underlying structural movement joint or expansion gap. They said that joint beads placed in elevations where the underlying structural base is continuous are pointless. Your render boards would be staggered jointed, and the basecoat will have a mesh embedded, and the render base coats are polymer modified to allow far more movement than sand/cement. So I think if you needed an expansion gap, you would need to incorporate it through the render board as well to ensure the movement was focused there, right through the build up.
  4. MarkyP

    Nail guns.

    I have a 1st fix hitachi, it did a lot of work during my roof framing, sarking fixing, counter battening and so on, saved me many, many hours. It's paid for itself in time saved, I really ought to sell it on but it's handy now and then, and I think I have a bit of a tool addiction. Has been reliable, good tool. The joiners I used to help me with some of the framing and 1st fix used paslode however they were impressed with my hitachi and it takes the same nails and gas. It's amazing how quickly you can get through a bit of 1st fix timber work with a gun and a cordless skill saw. You have to shop around for nails though as they can be expensive. When I was last buying I followed my joiners and bought Fox NailMaster nails, a lot chepaer than paslode and they worked fine and were decent quality.
  5. MarkyP

    Lean-mix cavity fill, the exact recipe?

    I think I got the idea from the Denby Dale passive houses. Mine looks exactly like your picture, albeit with a lower external ground level.
  6. MarkyP

    Lean-mix cavity fill, the exact recipe?

    Or chat your BCO and see if they will agree to dispense with the lean fill altogether. In my case ours was fine and I used 150mm eps to full fill the cavity below the tray formed by the dpm down to top of the footing. If I recall the leanfill detail is to prevent high loads from vehicles or high earth build up from pushing the block/brickwork and collapsing into the cavity. I think it's a bit of a belt and braces old fashioned detail unless there really is a build up of earth or risk of crushing. In our case the soil was 150mm above footing, sometimes less. Insulating to top of footings will improve the thermal performance of the wall by extending the heat loss path of the inner leaf.
  7. glad it went well. Only just spotted your earlier comment about the primer - when used dilute on porous surfaces it doesn't dry universally green, it does look a bit patchy and is mostly translucent, the green bits are usually where it's gone on a bit thicker. When used neat over non-porous, it comes up thicker, tackier, and more obviously green. Obviously an after thought now but may be useful for others
  8. MarkyP

    Plasterboarding on yer lonesome ....

    I used one of those board lifters to board out my extension - about 80m2 across two ground floor rooms with 15mm fire rated PB. Was a doddle on my own, the board lifter was great. The hardest bit was lugging all the 15mm boards in from the drive on my own. I've still got it for when I get to lining the upper floor in the loft conversion, £100 well spent and will get something back for it on ebay when I flog it. They are surprisingly well made and sturdy for the money but it is a bit heavy and unwieldy, wouldn't fancy using it off a flat, smooth deck. I didn't realise you could get an extension, should think it would be fine with one, they are very stable.
  9. MarkyP

    Celotex installed in cavity block wall build

    It's a topic which has been discussed in great technical depth over on GBF over the years. I recall a study showing that it degraded to 0.028 within the first 10 years, but even this would be within controlled conditions- a board with a perfect foil face and I wouldn't be surprised if edge sealed in some way. Would be good to know what a board with 100% air rather than pentane would achieve, that would perhaps be a reasonable backstop worst case lambda.
  10. MarkyP

    Celotex installed in cavity block wall build

    PIR boards have been shown in studies to lose their thermal properties due to loss of the pentane gas over time, becoming worse than the best mineral wool (lambda in the region of 0.032). Also the required void in a partially filled PIR cavity acts as chimney and /convection and air movement space, fully filled removes this problem and will make the wall far more wind tight. Also lots of discussion and reports over the years that foam boards are not brilliantly dimensionally stable, they can shrink and bow with ageing (a reason most system suppliers dropped foam boards as an option for EWI).
  11. MarkyP

    Celotex installed in cavity block wall build

    I saw a new build estate locally under construction with PIR cavity walls and stopped for a look, the insulation was ill fitted, gaps everywhere. I think its a case of out of sight, out of mind on such builds. But the thermal bypass must be tremendous. This insulation will be coupled with aerated block work to the inner leaf which will crack behind the dot and dabbed plasterboard = a nice steady breeze blowing through the plugs and under the skirting from the outside. Far, far better to go fully filled with a decent thickness of mineral wool. Makes it harder to leave gaps. We had some rubbish, really sloppy brickies on our blockwork extension but I'd gone for a wide fully filled cavity on the extension, even these were able to keep the insulation batts tightly fitted without too much mental strain, albeit with me checking it constantly.
  12. will the new weep holes do anything? I've often seen these on retaining walls and wonder whether they really serve any purpose. I would think they might perhaps in conjunction with a french drain, or some other means to create a space for liquid water to pool.
  13. I think the primer is to control suction in the subfloor, stabilise dusty surfaces and promote bond between the smoothing compound and the subfloor. It's used neat on non-absorbent subfloors, and dilute on absorbent surfaces. I think the can of primer is about a tenner, cheap enough that I'd never considered not using it.
  14. setcrete is really good quality stuff. It's actually a re-badged FBall product . The deep base is good, I used some just last week but it does have a grittier grain size and can be a bit harder to feather out thin. I would only use it for a deeper application. For 10mm or so, I would use the setcrete high performance levelling compound. This is good up to 15mm in a single application, is much less gritty and in my experience does flow and level slightly better. My theory is the deep base has a slightly gluey nature which is necessary to hold the aggreagete in suspension in a deeper fill. With setcrete you'll need to prime rather than wet the subfloor, read the prep guidance. Use the Fball/setcrete primer, it's green stuff, acrylic based. Adding a little extra water does help it flow but from memory it's recommend to use about 3.5l per bag, and I've added an extra 250mm to 350mm or so. Too much extra water and the suspension of the fine aggregates can be affected. I've used a fair bit of this over the years, just remember these are smoothing compounds which have self levelling properties to varying degrees, they don't self level all on their own! They all need a degree of trowelling out and careful pouring. A spiked roller brings it up to a lovely, pin hole free finish and removes trowel lines, but overkill for a one off job. one last tip - you can stick some window packers of appropriate size across the floor to guide your levels as your pour.
  15. I'm no expert on approaches to flood mitigation but thinking out loud I could see tea cosy approach being preferred over cavity. I think you would certainly want to avoid mineral wool in the cavity if there was a risk the cavity could be breached during a flood. The stuff takes an age to dry out once wetted (experience of dritherm32 batts left in the rain on my site) and when saturated tends to slump and deform. If going with EWI, then I would think an open cell insulation would be much preferred. EPS is open cell somewhat vapour open so in a flood the wall inside if wetted would be able to dry outward. Closed cell such as PIR or XPS I think would not allow this, you'd need to dry from the inside only. I think there are few system suppliers who specify closed cell EWI in any case. There were issues a while back with PIR boards used for EWI deforming once fixed, "pillowing" I think was the term used. Nearly all systems I considered were graphite enhanced EPS. There are some that offer wood fibre or mineral wool options but neither would be suitable where there was a risk of water immersion. I learned that EWI grade EPS differs from standard stuff. EWI grade it is cut from aged EPS blocks which are dimensionally stable. Standard EPS is not and there is a theoretical risk the boards could deform causing cracks.