saveasteading

Are you sure? If ever Ii have to get on steps so my head is near the ceiling, it feels much warmer there. If there is lots of movement and a lowish ceiling, then not so much.

The other factor is that a warm floor provides warm feet and a better comfort level than the air-temperature might suggest. Whereas ducted warm air rises straight to the ceiling. The higher the ceiling the more energy benefit. This will be especially the case in situations such as children playing on the floor, watching telly with the legs stretched out, and bare feet situations. Impossible to evaluate I expect.

I was about to say that any engineered floor needs at least a third layer as a 'balancing' layer to prevent warping. But ply should do that. How many ply, and how thick and which direction of grain is the outer one.? Quite a risk to lay all this and then it warps or splits or shrinks leaving gaps, and you have no guarantee. I suggest you ask the supplier to clarify whether it is, or is not, suitable for UFH. It cant be both. If not confirmed in writing then they must take it back. Or perhaps your Architect will guarantee it.. haha. I once laid herringbone using tiny wooden tiles on a mesh backing. They expanded more than the expansion strip specified, and buckled into mounds. so I re-laid them with even more expansion edge, and then they shrank and there have since been characterful gaps and lips, probably moving with the seasons.

I salvaged the bricks from some old storage heaters. Incredibly heavy for their size, and I am guessing there is a lot of iron in there. Why, you ask? They are in the greenhouse as plant stands as they absorb (a lot of) heat in the day and keep the plants a little bit warmer for a little bit longer. I have come across ironstone in excavations and the weight and heat absorption are similar, although the bricks were clearly manufactured to a precise shape

That is what the manufacturers say. But physics has not changed and energy in = energy out. What has improved is the control system for temperature and time. But it is still using electricity to heat a brick in the night while the price is lower: not really sophisticated at all.

Also, some sounds are more annoying than others. A distant motorway sound just like a waterfall. There will be a big difference in keeping out all traffic noise, as opposed to occasional big lorries/ sirens etc.

I think you have all the comments you need here now. What I would pick from them is. 1. tell them "I have done some homework and am concerned about the sand blinding. Show me something to confirm that your statement is correct, that this is a recommended procedure." 2. dpc, "likewise show me proof of what you think is an acceptable distance from new paving to dpc". 3. stop work and payment until you have done this. Where to find proof? Suppliers of paving products, Marshalls being an obvious one. for block paviours they will show a sand bed, but I think it is unlikely to be appropriate for slabs. However I can't see anything useful from them, but did find this. https://www.paving.org/index.php/how-to-lay-paving-slabs/

I would be more inclined to leave the PIR as it is bought and the hard work done, but then batten out twice to put in a layer of mineral wool, an air gap then a layer of any plasterboard. I don't think it needs acoustic seals as you have created a very long path for airborne sound. The shortcut might be by vibration through the roof via the rafters, so your resilient bar might be a useful insurance to break the contact to the pb. Is the noise high or low pitched, air-borne or including vibration?

I think they told me about £400/m3 plus 30p/m. Also that the logs were usually cut a year previously and kiln drying is then not standard or necessary..

Do it soon as fading starts immediately. At least the south facing as a priority. I would give it a month of dry weather to move and shrink, otherwise there will be some gaps at joints. I'm assuming this is straight from the mill and not kiln dried, and even that shrinks in my experience. I didn't get any suggestion of any discount from that supplier, but their usp is any timber size to order.

Because they are charging what they can, quite reasonably. I went to a small mill and they gave me a m3 price, but fairly said I would get standard timber cheaper at the merchants. JohnMo, that is beautiful. Are you letting it fade to dull grey, or staining it to keep the colour?

Until you have tried to lay stone to a level it sounds easy. The sharp sand is similar cost to the stone and much easier to lay, so saves labour. This will work fine for a number of years then will fail, and when that starts it continues. The guarantee, I guarantee, will be worthless as it will take you £1,000 of legals to get £500 of repair done. Unless thy of course the contractor admits a problem and just does it for you with a smile. be sure that they do proper pointing with wet mortar and don't just brush in a dry mix and assure you this is the best way. If they do this properly it will allow the rain to run off the edge and away, rather than through the sand. It is on a slope isn't it?

Can you ask them to show you any drawing or written spec that confirms their proposal? A lot of people on here will be surprised if they can.

I think the timber price is steady now, perhaps discounts becoming slowly available, and will drop a little more.

No problem: the discussion has grown towards general theory. Ask your supplier how they avoid shrinkage cracks at box-outs. Perhaps it doesn't shrink? Or they add fibre?

Recently Scotland has brought in mandatory, linked smoke alarms for every house, old or new. As most will be retrofit, there will be a very big market for wireless, so it will be interesting to see if the market develops.

It is standard in laying big concrete slabs, but must have a dpm above it. 1. it makes the slab a consistent thickness and therefore controllable 2. it provides a sliding layer for shrinkage 3. it is cheaper than concrete. The problems come when it is much too thick, as it isn't compacted well, and then gets footprints in it which may remain as voids under the dpm and cannot help crack control.

Yes. And tied with wire to the mesh, so that it stays tight to the mesh, and doesn't get displaced or even lost. This is really important to avoid big cracks from a corner to the nearest edge.

Can I ask why this needs waterproofing? Unless it is a basement or has a retaining wall element the only water should be dampness, not running water with any pressure. For dampness, an inner liner might be ok, but it will be forced off with any sort of pressure from outside, in which case the liner should be outside.

OK I do really know about this. Must have specified/supervised for tens of thousands of these, on mostly very big, but some small, columns. Gus and others are mostly right, but my opinions are based on the difference between theory and practice. You perhaps don't need the theory so here is my suggestion. For a small column, as this is, pour the concrete base solid with no bolts, to 20mm below the base plate level. Make sure the Engineer and/or steel fabricator have not already allowed for this with a shorter column. (That would be clever of them but a nuisance if you do it too). Check the column length on site too, as fabricators have been known to cut the measured length then add the plate. Then you can mark the bolt positions absolutely precisely and drill/ stud/ epoxy. (quality important, see the instructions, and supervise the work) For shims use square fence washers, 3mm thick so you are never more than 1mm out. They will squeeze down a bit when the nuts are tightened. OR (my choice) set spare nuts on the stud to the plate level. Then there is nothing in the way of the grout. Grout up using a stiff dryish mortar mix. Use small size ballast if you can get it, otherwise sharp sand. push under and ram it hard to refusal, so you need a back stop board. Flaunch to vertical or 45 degrees. Why not use expanding grout? Because they tend to assume it is magic and leave it well short of the plate and with gaps in it. Use it if you like but still supervise.

Yes be concerned. I think this is just easier to lay flat than stone. It can't really be rolled or whacked hard either. The problem I see is of rain running through the joints (perhaps in 2 to 3 years, and washing away the sand. As suggested above, if it has enough cement in it then it will be ok. but I think this is just to suit themselves as it is difficult to impossible to lay stone exactly within a few mm..

I would make a real hash of that using a hacksaw, but perhaps a more skilled person would not. Tin snips are very tricky and would not be very straight, but that is what a skilled metal-worker person would most likely do on site, using all three left, right and straight-cut snips. I would probably try a chop saw, assuming there is a metal blade available for it, and first put a timber stiffener into the section to stop it deflecting during cutting. I think that is basically what a window manufacturer would use, albeit on thicker metal.

Because it doesn't burn there, and the only other option is polystyrene. There are signs that PIR costs have steadied. Locals advertising leftovers are not asking for list price (or higher). I am wondering if my post above would better be in a new post, rather than attached to the Grenfell discussion.

Yes, uploading the application today. PIR under the floor, where we only have 100mm available in some places because of existing floor and lintel levels, but will put as much as we can in where levels allow. That is all though, elsewhere will be mineral wool, plus lots of cavities for damp and services, and supplemented by wood-fibre board where we don't reach the targets. Although we only have to reach 'reasonably practicable' insulation , we have hit the target using 'area weighting'. and all areas are close in themselves. I had originally misread the standards, and thought we were a long way inside the target, but for a cold unoccupied building the targets are close to new-build. We would have aimed for this anyway. In calculating the wall effect, 600mm granite, I have used the figure the Scottish Government suggest for assessing old buildings, based on real tests, and that helps a lot*. Have also taken the advice on not ventilating the air-gap between wall and new internal stud, as that would suck out all the heat. so have allowed a compressed mineral wool seal at the head of the wall, closing the gap to the roof void. I don't know any figures but expect that our single-sized sand ground will also perform much better than 'normal' ground. It will be utterly dry. This will partly help in the heat loss through the ground due to the outer walls all being so close together. * Studies show that the central core being over 40% mortar helps a lot, so the granite does not absorb water and thus does not lose heat in wind drying. The mortar gets a bit damp but it migrates down. The bottom metre is damp all year, but of course is the central bit again. We are showing a hyload bitumen sheet to the inside bottom metre of the wall, to keep the damp out, and then hoping to resist any BCO suggestion to ventilate the void to let all the heat out.

It doesn't help that there are class O and class 0 ratings (that is Oh and zero). I have been at a furnace test, and don't doubt the integrity of the test labs. My main memory was of how hot it was on the safe side of the furnace, before it was deemed to have failed. But I learned on a fire engineering course (implied not stated) that the labs can only test what is sent to them, and to the level that is requested. Hence a 1/2 hour rated ceiling with no tile clips might well pass a 1 hour test, but wasn't tested to that level... (I guess the manufacturer instructs that the test is terminated after 1/2 hour) Then the test with clips is done to show a 1 hour pass.