saveasteading

It's a car port. If it looks OK it is OK. I'm not doing any calculations , but suggest doubling up the big ones, bolted together. Ie 2 instead of 1. Once it's built, if it feels OK, that's it, if it doesn't, ask again. Failure would be from snow load, drifting against the wall, so clear it, or stay out. Def diagonals at the beam to post junctions for stiffness. Will look better too.

I showed this conversation to a family member. Architect capital A and contractor. Agreed completely with @Alan Ambrose. An @Icevergetype 3 fairly obviously. You are right. Finding the right one for yourself isn't easy, and the wrong ones are easier to find, being better self publicists.

Insulate if you can. Not necessary perhaps, but much to be preferred. Even a few mm if that is all that fits. The mass of the wall is very handy in keeping summer heat out, but not winter heat in.

Lime. Builders and consultants often don't understand it. Have a read and then you will decide it is the right thing to do.

You do all that work and there is nothing to see.

Nerdy extra Invented by Bosch SDS short for “Steck-Dreh-Sitz”, Insert_twist_ secure later “Spannen durch System” and today “Special Direct System”.

I've been reading up on sds plus or max this week. That's because we have to make hundreds of small holes for 12mm studs tying existing and new slabs together. Sds max appears to be very much heavier duty, for wide diameters. So for our small holes we can use my battery Einhell and our groundworker's battery one shuch I think is milwaukee. But I have found that the bit quality is even more important. So I have ordered 2 from the BM and more from a specialist online. I'll report back. For a few very big holes I'd suggest hiring an SDS max and buying a new bit ( or hiring if the price is ok). You'll always get a hire at half the published price, and it should be quick. Ask for one day and they might throw in a few more days.

That's a good principle. I think it needs a name in German or Norwegian. Stockhausen? Nahehaus? I'm only guessing and amalgamating many measures of quality but I would boldy say that 95% performance is indistinguishable from 100%, and the cost saving is 25%. Turn that cost into carbon by any means that suits the argument, and 'near ph' is better.

Ouch. The terms reverse according to UK location, and one is not better than the other.

I was very surprised to see how little extra it costs. That's assuming you don't have to pay for a transformer. But single phase seems to be plenty for a typical house so why pay more?

A kettle and a toaster? Have to turn the ashp off during breakfast.

@scottishjohnA relevant degree and 50 years working with steel buidings wasted? Maybe I'm explaining badly. I was expanding on the query by @Iceverge so maybe it doesn't coincide with your post. May be the confusion here. Is the other confusing factor. It will buckle unless restrained.

They can be and are, for big structures. The standard ones are "hot rolled" through formers from a yellow hot balk of steel. But beams can be welded from flat plates which can be whatever thickness and width is required, in which case they don’t even have to be parallel. Your picture shows the possibility of increasing the web height from a hot rolled section. Castellated beams are cut to zigzag halves and moved relatively sideways and welded together. The weld is visible in your picture. The circle option is a prettier effect, with some offcut waste resulting. Very strong and allows services through. Also note plate girders on victorian bridges, made from flat steel plates riveted together.

Sorry, no. The web (the central vertical bit) is there to keep the flanges apart. Then it has to resist deflection but that is secondary. Increasing the distance the flanges are apart increases the lever for the flanges, and making them thicker gives strength....but it's a class for another time. There is permanent deflection from the load above the beam, and that doesn't concern you ( it bends and stays put, and the door gear can be fixed kevel). Dynamic deflection from the doors moving is your concern. (Loading and unloading). There is no such thing as zero deflection. Thus it may well be ok, but probably needs clarification.

May I ask why you want a slab with a fancy name? If you stick with traditional methods you can use local builders and get the same performance, or better if you want, and way better value. I think most people on BH aim for "Near passive" levels, because of diminishing returns seeking the last few % performance. That starts with the floor.

This is becoming non standard but then so is ( to me) having insulation straight on stone. So I'm going to say, stone as thick as you like...but at least 100, laid really flat and with 0 to 10mm max sand blinding but zero if you can. Dpm, to radon spec if necessary. Then a concrete screed about 75mm, hand tamped and nicely level. A light mesh (A142) would be a nice touch. Shop around. 150mm insulation Dpm, taped, any spec as it is only to close the joints. Ufh pipes pegged to the pir. 60mm pumped screed. I like the level control in this, so the thicknesses are controlled. Plus having the lower screed keeps it all clean and the pir laid solid. BUT it depends who is doing it.

Sounds to me as if that needs no further treatment. What is behind the ceiling that might burn? I would need to know the steel section reference. I'd be cheeky and ask bco to answer the query from your fire engineer: what risk he perceives (where is the fuel behind the ceiling and the likely ignition. Given the HP/A why does he think it needs more protection.?

Let's go back. Red oxide gives no protection. Self applied fire paint works as well as professionally done. You do need to prove the thickness. Not all steels need protection if very chunky. How much is exposed? Lengthwise Cross section. There are several means of achieving this. Bco has done an hour on fire. I've done a serious course and argued on such several times. I might have forgotten of course. The bco never admitted to being wrong, but found some getout. Same result. Is it behind a ceiling , as mentioned? Cables are a potential source of ignition not of conflagration. I assume you'd like to say: no further protection is required.

I don't know the product but have read the advertisement. At £120 per big bag of 1m3 that will be £18/m2 plus vat for 150mm thickness. Pir is much the same I think. If you can replace sub base thickness too then it looks promising. BUT I expect you need a board on top of it for level control. So 100mm plus 50mm board???? I'm interested, you can see.

You only need one layer of plastic. Choose a radon spec and it does the dampness thing too. You need an extra plastic layer on top of the pir as it stops concrete or grout from running into gaps and floating it. I've seen it and isn't fun. Screed or concrete. Either will do. BUT I would say put a thin concrete screed down for the pir to sit on, and then 60mm pumped screed goes on top with the ufh in it.

It's not over the top at all. Build it properly with a concrete floor, fully insulated. But I'd advise against fudging this to avoid planning and building regs. We have a system gor a reason, and shouldn't avoid it. If the propriety doesn't concern you, then think of the risks in being forced to remove it, of not being able to sell. Yes it will cost a lot more. Exactly. Do it properly.

Yes. It is all covered in the building regs where graphs show grades. Let me know if you need help to find it.

But seriously. Is this outbuilding for a potting shed, or sitting with the newspaper for an hour occasionally , or an office.

OK. what thickness might help you practically? This is a house so nobody is going to break the floor. The weakest layer is of course the insulation. After that the loads are very well spread over the stone below. If the hardcore is good quality , ie not a heap of old bricks, then that can be reduced in thickness. Likewise the sand. The sand is there for adjusting the level so there might be none above the highest point in the stone. so i am suggesting 100mm concrete, on 150 PIR, on 150 of stone and sand (total). that is still 400mm which is a lot to dig out, but a lot less than 500. IFFFFF you do it to a high standard of level control and compaction.

If you haven't already, tell them in writing that they are suspended and you will make no payment while you enquire about how to proceed. That will include mortgage advisor, bco, the ARB, and a construction lawyer. If that doesn't get a compromise or a walkaway, I'll be amazed. That is of course if they are ARB registered. What does it say on their blurb?