saveasteading

If anyone remembers slide rules: digits were shown as an answer, but we had to know ourselves where the decimal point went. In a complex sum, it required a bit of working out. But with this sort of calculation, it is common sense. What sort of number do I expect to see? 7mm or 70mm or 700mm or 7m? The answer here is fairly obvious and it usually is. Assuming the calcs are right and the fundamental principle is valid.* For example, I offer each school client a practical maths class. the first challenge is how much concrete do i need to order for he floor slab. H x L x th. decimal places are always the biggest challenge. So I help by asking how many concrete lorries feels right? for example is it 3 or 30 or 300? some kids immediately feel what is right, but others don't. It's the way our brains are wired i guess. Now, from a quick look at your link... *Rankine's formula doesn't, as I recall, apply to foundation depths. But he did a lot of stuff so..@Gus Potterhelp please. There is no such thing as The Institute for Civil Engineers, not in UK and Commonwealth anyway, It is the Institution of Civil Engineers, and these are not they. Who knows who wrote this googled page? So to your wall. I wouldn't calculate this, as its not exactly a motorway where disaster could result. 700mm seems very deep to me. 450? /500? just do what feels right. If it fails it will be by falling over, not settling.

There are only a few doing that, and they criticise everybody other than themselves. As I mentioned before, I wonder what they do as jobs, if everything they do is perfect, and how much they expect to earn.

I have only encountered one, and their attitude to tenants was appalling. Defensive and patronising are the politest of the words that come to mind. I hadn't expected that. Yes you need a 'building engineer', perhaps called a construction technologist. They could be Engineer, Architect, Surveyor, or a builder, ut not just any one. Someone who has seen it all before and understands both the sources of damp and building construction. That's all very well to say but I wouldn't know who to ask in my area. A few of us on here clearly would have a decent idea, but they probably don't live near. Anyway, as above. if a problem has just appeared recently then it should go away again, or there is something that can be sorted. What is different this year? Did you have any exceptional rain? it can take a very long time to dry out. The first thing I would look at would be the external levels relative to dpc and air bricks. then lift floor boards as @ProDavesuggests. you might well find water and mud sitting under there. that would b e good, as it is sortable. Have you any pictures to help us? any signs of problems, and the wall outside even if it looks ok.

Because of the potential greater heat losses. I wonder if there are. I don't know, but my gut feeling is that it is minimal difference. The easy route for the heat is upwards. Not considered a problem raising mesh up 50mm or so, and not considered a problem attaching UFH pipe to steel mesh. Unless the mesh is only for that purpose, so adds cost. Probably not that hard to get different height posts that are suitable to attach UFH pipework to. May seem extra work and expense, but probably isn't in the scheme of things. Yes i thought of that too: just a bit more plastic under the peg, as a spacer to keep the pipe off the pir. But then it is a problem and risk moving around n between dangling pipes.

@Jenkiused them i think. I wonder how his slab is looking.

Doesn't trouble me. Explain why I should be troubled please? Having recently seen it done, and the (low) level of skill and care, I'd rather the pipes were on the solid bed when they get walked upon, and it means they are all at the same level.

But if the screed is 60mm there isn't a choice, and clips are sold precisely for this.

The concrete or screed supplier can add them to the mix for about £10/m3. Thus much cheaper than steel, esp with thin slabs. For diy it is a small pillow of fibres. Without steel, these fibres should allow panels up to 4m x 4m.

A bit like icebergs bobbing up. I had a plumber who insisted he was expert in UFH (before it was common) , and that he had to include the screeding in his package. An open plan office area of about 200m2. The PIR floated up, he panicked and my masterful management skills kicked in, amounting to: stop pouring: bring in concrete blocks to lay on the pir : start pouring. It could have been much worse and fortunately I had felt the urge to be on site. This was with taping of joints but not a plastic sheet as well, which is optional. Tape should work but clearly is fallible*. The cost of the extra sheet is not much compared to the risk. * I think the issues are where tape is loose, or has come off, and at edges where it isn't fixed hard.to anything. The downside of a top sheet might be that it conceal gaps in pir or the use of multiple offcuts.

Underneath as a dpm. Also on top, to prevent screed getting under the pir and floating it....which is not a pretty sight.

Architects overcharge and are impractical Engineers overdesign Builders are all cowboys. Surveyors get in the way. Planners are unreasonable. Building Inspectors are too fussy. Clients? it's a shame we need them. Don't worry BH is here to help with fair and polite enquiries.

Absolutely. As you say, there is a big difference between drawings for planning permission and for construction. Complaining parties wouldn't be best pleased if they had to pay for full working drawings, if all they wanted was planning permission. On an uncontroversial site, with an uncontroversial proposal, the building is really just a picture. Of course it should be build-able. but the fee may not be high because not a lot of time is required. Building reg and construction drawings are another matter. It may be a surprise to many, but, with my contractor's hat on, we hardly ever adopt any drawings supplied to us, and prefer to start from scratch. I think this is pretty normal for any contractor with design skills in house. That way we aren't picking up any scale or perspective errors, and we have it on our own preferred design suite. An Architect providing the next stage can, of course, reuse the planning drawings and add to them, but it may not be the best course of action. Too much or too little? The client's fee will vary according to this, and the procurement method will be important to this decision. Differences in the amount of detail may be appropriate. A traditional construction, being carried out by an experienced main contractor doesn't require as much detail as it would if going to an inexperienced self-builder or a series of unrelated specialist contractors. I don't know what the cost is for a bull's service. It probably depends on which part of the bull is wounded. It made me smile though, as did rugby commentary last week that x was 'like a one armed matador.'

You mean that? I've done that several times. Even once with mutiple ibc units linked to store 6m3. Not pretty but an industrial unit, and avoided the EA suggestion of a green roof. So client v pleased, and EA too. This works so has to be better for downstream people than a drain straight to ditch. The bco may not be bothered, but i think we all need to do what we can.

Prevention against corrosion can be relevant for an outdoor slab, but doesn't apply to an indoor slab as it is totally dry. Mesh is used primarily for strength and secondly for crack control. If it wasn't needed, and wasn't present, then there wouldn't be any reason to protect it. Putting a single layer approximately centrally ensures that the slab stresses are balanced and it doesn't curl.

Correct. I wonder if the op is satisfied with the answers. Obv mist people are saying its over 1,000. I'd venture 3k is typical for a reasonably traditional design where most details are standard, and without PM role.

My apologies for teaching you how to suck eggs. your question therefore is only about what will heat the room best. it won't make a huge mount of difference i don't think. But for your immaculate floor surface the pipes would best be tied to the mesh in mid slab, where concrete gets all around it. also no risk of the chairs sitting on pipes.

If you are having 125mm concrete, i think mesh supported on 50mm packers is about right, then the pipes will be mid slab. The mid height mesh is best for the slab strength and allows concrete to flow under it and around the pipes. mesh at the bottom of 125mm concrete isn't great. Normal but not great, especially if you want a good finish. It's all different with flowing screeds.

It's ok but 125 is better. the sawcut is the tidiest as it is exactly where you want it. Inducers are plastic things placed below that spot to make the slab weaker at that precise spot, but the cut should be enough . It would have to go full width though including the doorway, and all the way to the walls. i don't know if that works for your intended slab.

Cracks do go right through. It can't be avoided. That isn't a problem structurally as there is aggregate interlock. (If they don't go right through then there really are problems with curling slabs, so let's not go there) ut it is the visible part of cracks on the surface that matter aesthetically, so seal them to prevent spillages or mop water seeping in, and you are probably going to be happy. However with careful preparation at the perimeter, crack inducers under partition walls and quality control of the concrete, the cracks will be minimal. The use of steel mesh, or fibres, will make the concrete crack infinitesimally all over and avoid any bigger cracks. But most importantly, keep the concrete as it comes. Give instructions to workers and the delivery driver that no water must be added. Surplus water evaporates and leaves the equivalent space within your slab. It does other stuff too, so never add water. But then, after the concrete is just hard, cover it and/or or spray it to keep it wet for at least a week. With your expectations I think do this for as long as possible, 2, 3 4 weeks.

This is what I have been assuming all along, rightly or wrongly. I can't see any justification for using a septic tank if a treatment plant is feasible.

Why not? It may be relevant to choosing an architect. Many of them wear "look at me, I am interesting" shirts. And scarf. And hat.

I've said what I think on this before. Some people like it. Are you meaning that you will have the surface ground back to remove the surface and reveal the stones?

That's probably what I meant. The night storage point is good...if you can store cheaper energy off-peak.

No. Energy in equals energy out. Assuming there is plenty of insulation, the energy will all end up as heat in the room. It will just be a bit slow to affect the room after turning up or down.

No. I started a response then stopped. Just no.