saveasteading

Marsh are my favoured suppliers. Small business, really good advice on the phone. Also they deliver themselves (regardless of the merchant you go through) and are as keen as you are that there is access and offloading organised. just an air pipe, like in a fish tank.

Hadn't heard of that one, so not adding it to my list...yet. On the contrary, if winding very slowly clockwise, the thread gets well filled. Perhaps it depends on the material and the amount of stuff between stud and concrete.

From recent experience, a temporary caravan is permitted in Scotland. This is perhaps more relaxed because of the 3 year requirement to complete after warrant. In England I think, put it on the drawings, as mentioned above. A nice , 2 person plus living space (described as 4 berth) can cost £8k to £12k, depending on condition. An 'end of life' or 'tired' static caravan from a holiday park can be very cheap, even down to say £3k, but then allow £1k for transport, and then quite a lot of cleaning/doing up. Afterwards you have to sell again and transport or scrap of course, whereas a tourer is easy to move on.

Agreed re contaminants/chemicals attacking the concrete. In some regions/ situations it is even necessary to put dpm between the ground and footings. With the dpm below, the concrete will forever be dry and inert. Another reason for the dpm being under is so that the concrete pour is clean. Sand and stone should not mix with it and diminish the concrete quality. Also, delivered concrete has a precise mix of ingredients, including water. If poured onto a dry stone or sand surface it will lose water and the mix is changed. And then there is allowing the concrete to slip on the surface while it cures and shrinks, reducing cracking This matters a lot with a commercial building. A lot of it doesn't matter too much with a house, where loads are low, and there is a layer of insulation, then screeds and floor coverings. ie an inferior job gets by , usually. But why not do it as well as possible?

If the made ground settles, then the insulation will go down with it, and you will have a gap between insulation and floor. If this gets any draught at all through it then you will have lost the insulation effect. I am really surprised that this is being allowed by BC but more importantly, you should reconsider the whole thing for your own heat economy and comfort . Perhaps you can tie the ins up to the floor with wires. I'm also a bit confused by the drawing attached by Iceverge. Perhaps this is much simplified by the company producing it, (to sell insulation or pipes?). There is no mention of stone base, on which there would be blinding. then normally dpm on that before concrete/insulation/screed. Getting pipes through the floor at exactly the right position is tricky. what seems very precise at foundation stages can be annoyingly approximate when you find that a vertical pipe is too close to/too far from a wall. There is a lot to be said for keeping boxouts around the penetrating pipes, and adjusting/infilling later.

my own opinion is that 50mm of sand is too much as it is difficult to keep it from kicking up, 40 scalpings and 10 sand good, which may be what you have in mind anyway.

No problem then. The only issue I see is that the very big stones sticking up might rock, so give them a bash before the scalpings

I have been subconsciously thinking about resin anchors. 3 more bits of advice, for big jobs really. 1. Do not use a diamond drill as they make a beautifully smooth surface. You need a rough face to the hole, as created by an impact bit. 2. If outdoors, fitting foundation bolts for example, then the holes may fill with water. That is when a stick and rag can work, when a puffer will not, but this is not mentioned by Hilti et al. Check that a damp surface is ok for that resin. 3. The resin is very temperature sensitive. After mixing it can go hard in minutes in a hot summer's day. This can be very difficult to control as there are seconds to do the whole thing. Also you may end up using a nozzle for every bolt. The reverse is that it may not be set next day in winter, and there are low temperatures when it should not be used at all. The instructions are usually good on this, so do follow them. I think that now makes 12 points of concern/control. That does not mean that I don't like resin anchors: I do, but instruction and supervision is important, as the consequences of any big anchors failing are worrying,

The anthracite coating is incredibly thin, perhaps 80 microns, and should not be reduced. There is no underlayer as with a car, and you are straight to the aluminium. Soapy water and gentle use of a soft cloth is the only option. Otherwise let the weather do the job, with cold rain in the winter, and warmth in the summer it is likely to come off in time. The roof will get dirty too, so it should become invisible. If you only have dirt you are lucky, as gritty feet scuffing can make a right mess of a roof sheet. It still should not have happened as cladders should know to either keep feet clean or use walking boards. If the muck is grit then it may be pushed right through to the metal, and you can ask the roofers what they are going to do. What do you think the marks are made of? Is it soil/ cement dust/ grit? I may have some more suggestions if you know.

That isn't too good. The stone seems lumpy and not especially well graded (finer stuff that fills the gaps all the way through.) Also too rough on the surface, so you should spread fines on it, sand or stone dust. The trouble you then get is that it might be rather thick and will take foot prints. Why does a smooth finish matter? 1. your dpm will puncture when you walk on it or pour the concrete, and might have air pockets left at high stones. 2. all concrete shrinks, and should be allowed to. With this surface it will not move where rough, and cracking is likely. Difficult to tell the scale. What size would you say the biggest stones are, roughly? How big is the floor area? As to strength, I can't imagine you will ever fall through it, but there might be chance of some movement and cracking over many years. as the stone seems to be so variable

We are at a similar stage and I asked the same question, the answer was NO: use a single Heat Pump, and spread the water by a big feed pipe to a second manifold. This just as a starter, and I refer you to the experts who will follow with more detail.

The sketches are a great help. I am thinking that we have different understandings of what a suspended floor is. Your concrete slab appears to be sitting on a bed of polystyrene. Suspended would normally mean spanning freely from one structural support to another, and so is unlikely to be on top of polystyrene, especially an exact contact. If the slab depends on the insulation for support then, I would not be happy with cutting lumps out for the drainage. Your second sketch is more normal and appropriate. I would also question why the builder does not want to put the drains in the ground, which is normal and easy, and proven. What stage is construction at now?

In Scotland it is compulsory to show an area that can be used as a work space, even including sufficient socket positions. This does not have to be a discrete room but can be in a hallway if big enough. Perhaps those who know can say how long this has applied.

Just remembered with a shiver...no it wasn't the worst. The worst was when a truck hoist fell over (with 5 tonnes of truck) because a base anchor pulled out of a slab. My slab but the client's hoist installer. They had only used 12dia expanding anchors 75mm deep into the floor slab. Should I think have been 16 dia, 200 deep. By the time I got there the client had realised not to blame me. I got the chance to see a genuine (not lab) failure, with the perfect cone shapes of concrete attached to the bolts that had pulled out. A demonstration of how the depth makes a disproportionate benefit to the strength, as the surface area of the cone increases. I didn't ask about the state of the truck in their time of stress, but nobody was hurt, very luckily, as the mechanic had heard the creak and dived for cover. Hoping not to dream of any other horrors.

If you calculate the volume, the difference between 1mm and 2m is obviously about double, less the thread, so can be a lot. Buy plenty of glue and mixer nozzles. Yes follow instructions, but no bigger hole than they say. The builder will use the drill bit he has, and you will be off to buy the same amount of glue again. It is worth buying a nice new bit to the 0.5mm. Often the rods are a smaller dia than stated. And it goes off in the tube in a year or so, so don't buy too much either. The glass vials can go wrong too, and the advantage is, I think, only that it is pre-measured. Oh, and you can more easily do them one at a time. I prefer to see the 2 parts mixing to a single colour, and knowing that is one of the many possible errors avoided. On the plus side, I have not known a properly fixed resin anchor to fail, but have seen expansion bolts working loose. Very good point about the grade of steel. If they can't tell you, then don't buy it. If ever wanting lots of stud, it is about half price from specialists on-line. All grades and finishes.

F But is your builder? For your purposes I would get it from toolstation/screwfix/ merchant. £8 for a name we don't know, or £9 for Rawl. She special gun is about £25, or you can buy little job kits. Show your Engineer and get his approval.....yes so choose a known name like Rawl or Fischer.

I mean common drain pipe with no ridges.

Any make at all is hi-tech by default. If building a bridge though, best use hilti or other big name. Lessons from experience (other peoples mistakes!), and some r and d of my own. Get a drill bit only just bigger then the bolt, otherwise you use a huge load of resin. Clean the hole thoroughly with damp bottle brush or rag on a stick.. If being flash get a puffer and a bottle brush. Use a longer bolt and hole than recommended as there may be some poor adhesion along the way. The outer 25mm does not contribute to the strength very much. Do not use resin fixing in walls with voids, or the glue disappears, although you can get some stent type inserts for this. If cutting dowels to use as bolts, screw a nut on before cutting. When you take it off it removes the rough burring. When mixing the glue in the provided helical nozzle, the first lot is often only one part and has to be thrown. Check the colour. Rotate the bolt gently in the hole while inserting into the glue so that it gets the glue on the threads. Also it picks up residues of dirt and take them safely into suspension. (if you just push in, it pushes out the glue, leaving air in the thread where glue should be. Best to have a little glue protruding so you know it is full. After the first one you can adjust the quantity. SUPERVISE, it is far from foolproof. My worst example was turning a nut onto a 30mm, 400 long rod, (one of 4 to hold down a 10m high column)....the bolt pulled out with the turning of the spanner. When it works, I prefer it to expansion bolts.

Yes. Used it for extract fans, including multiple intakes from an inline fan downline. When you take out old spiral stuff you see how filthy it gets because of all the shapes and ripples in it. Round pipe you could even rod if you wanted. that is drain pipe to me. perhaps there is wonderful new stuff I don't know about. this is only my opinion. I last used flexi on an extract fan so am not against it...but it is so flimsy.

Drainpipe. Easy to get, smooth flows, solid, proper, sealed joints at junctions. Doesn't rot or scuff or get eaten, has standard brackets for fixing solid, can change to rectangular at tight spaces.

Thanks. I think I was told this before. There is no mention on the page about expanding so I assumed it didn't. Got a family workforce on it over the weekend: got to use the early enthusiasm., So will check out Inverness Toolsation. btw we haven't started new works...this is replacement of existing rotten boards on solid joists, to keep the floor intact and stiffen up the building.

Many of you have recommended expanding chipboard adhesive. I can't see any at Toolstation or Screwfix. At buildbase it is out of stock. Travis and Jewson's are £16 each, and perhaps not in stock...any suggestions for where to find it today in Inverness.....where all major suppliers seem to be present.

Can you sketch one then please, then attach as a scan or photo, as i am not understanding this. Where is the insulation for one thing.

Explain please. If the concrete above is suspended, is it not still sitting on the insulation?

It might work. The loss of insulation is very small. My worry would be that this is an experiment. The pipes would have to be carefully laid to gradients. which could be tricky. On a concrete bed, and probably surround too. Then the upper insulation is sitting on a bed of concrete very locally and there could be differential movement. So no, I think this is a bad idea.