saveasteading

If it was the fee would be very much higher. Some good BCOs are very busy dealing with problem jobs, and the deliberate cutting of quality, and so see the rest of us less often. I give them the benefit of the doubt, and don't expect them to know everything. They are allowed to be mistaken, but I would expect them to back down when necessary.

I hadn't thought of the sarking as a top flange to the roof trusses. Probably because we do have some outward leaning walls. This is now a clincher in choosing to use OSB rather than traditional 200 wide timber boards with the 2mm ventilation gap, wherever we have to rebuild. The 2mm gaps are enough to allow the rafter to bend upward and outward and to lose the flange benefit. From my current homework, the guidance for a new timber structure is to have a structural pod of a controlled area, and to further stiffen by building cross walls as stiffening. It is not there to stop the roof from splaying, but it will. For normal sized rooms this is straight forward but requires more foundations and OSB on the partition walls. The same logic will apply with masonry walls. JackOfAll....do you have normal or big rooms?

This is now available in any Google search. I hope your alias is obscure enough. But you are right on the rest. I had the misfortune to manage an underpinning process many years ago, The company had tendered and won it, never having done it before. Doing it properly was much slower than they had estimated. My boss, who knew very little, insisted it went much faster, affecting the amount undermined and the shrinking /packing process, and I moved on to a better place. I am sure the same still happens. The building inspector does not inspect often, or in close detail at all. If I was an insurer I would not be interested. Mr Punter is probably right though...there is no current problem (only a concern) so it is simply covered by your normal building insurance, who would then sue the builder and Engineer if there was ever a problem.

Batt insulation is half the insulation performance and isn't enough Sprayfoam, no never. blown in....polystyrene balls or newspaper....no thanks. One chance to get this right.

All very good info and a brilliant document I had not seen, thanks. From a very quick look.....and some guessing. Impervious granite with small percentage of mortar on the faces, (therefore dry ), huge percentage of mortar in the middle which, as you say, has a decent thermal resistance. I will have a detailed read.

I agree re the labour on the timber, and another element of wood to add back in to the equation, but perhaps a detail will present itself. On the other hand, cutting PIR into the voids is also a horrible job, and that labour is reduced too. I didn't mention that the rafters are very approximately 18" c/c. Can be anywhere from 380 to 420 gaps. I thought these old builders were more precise than that. Perhaps with 600cc the c/c will average out. Every piece of PIR in the roof will have to be measured.....grrrrrr. As posted elsewhere, we have rerun this wall liner with 100mm studs and it is good for insulation, so that will save us a lot of timber. Also I have found that standard CLS (or near) can be much cheaper if bought by complete pallet, effectively straight from the docks with no handling by the merchant. I'd like to use local timber, but the mills say that Russian/Finnish will be cheaper for CLS. I'm not so sure. published local price for C16 treated is 100mm x 50mm x 3.6m £9.18 Excluding VAT that is per one, collected, so there will be discounts. We will 100 x 50 (or 38) at 600cc and reconsider later, especially for the longer sections. Then if we revert to 400cc there will be no prob from the BCO.

There is every reason to assume that your own work will be diligent and thorough, and possibly better than some contractors. They don't always put their best people on gutty work like this. But I'm not confident an insurer will be excited about the business as a one-off. If one Engineer says it doesn't need it, then it does seem completely precautionary by the other, or a marginal decision. Which one seems the more specialist and experienced in such works?

Have done further consideration and re-analysed the U value. we are now 600 granite (in 3 skins) 25 air gap VB 100 stud with PIR VCL 25 air gap and horiz studs pbd. U value is about 0.15. a lot of this is because the 25mm air gaps give better values than if filled with rockwool unlikely I know, but narrow gaps do work quite well. Also Granite is highly rated by heritage building authorities, as providing 'much better insulation than the regulations and standards assume'. I think this is because of the random 3 layer construction, and that there is relatively little mortar in the faces. As we don't have to match any standards in a conversion, we are happy to believe what we have come up with. Also, the reality of the stone walls is that there is hardly any dampness on the surface, for the wind to evaporate and suck out heat. granite 2.6tonnes /m3 and stones averaging 300 x 300 There certainly wont be summer overheating through the walls. The Standard states Wall studs to internal racking walls should be at least 38 x 89 size, grade C16 at 600 mm centres. and there does not appear to be any situation that reruires more.

Ok I a am a cynic. But whenever I have had a recommendation from a specialist, for methane usually, they have allowed complex ventilation underneath as well as seals, and all to be carried out by a specialist installer. So I looked into this is a big way, as I had several jobs on or near landfill. Since then we did it ourselves at about 1/4 the cost. It still needed physical ventilation beyond a certain distance from the outside walls, and in one case (because of distances,) a constant fan. The difference in cost, apart from margins, was that plastic pipes came without 'methane pipes by the acme safety company' written on them. ditto the membrane, So by all means get it designed by a specialist, but I suggest diy, or by the builder with close attention to quality. Ventilation or not will depend on the distance to the perimeter, ie size of building. It is an a fairly accessible document. Perforated pipes under the building, or ventilate the void, as applicable, with the barrier in place and sealed everywhere. The gas just wants to escape so make it easy

I see what you mean. Specify as in 'state that it is a design requirement', or specify as in 'choose a manufacturer? AS I understand it, it is simply a dpm where the plastic is right chemically and in thickness that gas with radon in it can't get through. It used to come from very specialist suppliers with 'danger radon beneath here' written all over it in red on yellow. Now it comes from toolstation for £0.70/m2.

Sorry. sounds like an obscure specification. I meant that it wasn't new (and not anew problem) , perhaps very old.

Thanks. That is what I would expect and want, but it didn't look that much.; The design guide accepts down to 38 x 89 @ 600cc which seems tiny. I haven't looked at how small the building and benign the conditions for that.

Whoever is presenting the design. Architect, Engineer, yourself. Simply look up the definitive website and pay for the information. About £3 if I recall. Answer emailed in a few seconds and you simply include that page in your submission. The extra cost of a radon rated dpc isn't as bad as it used to be. http://mapapps2.bgs.ac.uk/geoindex/home.html?layer=BGSRadon&_ga=2.106057667.1323565302.1635198583-1743045500.1633718990

Either it needs underpinning or it doesn't. Partial underpinning is an interesting idea, as you are undermining the building then trying to wedge it up tight again. It is rather a primitive process, and I always thought would cause a mm or 2 of drop. For the whole building evenly that wouldn't matter, esp as it is usually because the building has already moved. Not knowing the reason for the precaution, I wonder if there is another means of spreading the load away from the corner he is concerned about.

Up til now I had thought how easy it will be to stud internally up to the exiting roof trusses. An approximate cut length and a screw into the side and it is done. However, as it just occurred to me, 600cc is plenty for internal use, and it reduces material and labour costs, and also reduces the cold bridge of the timber and improves insulation How best to do this? So far I have only thought of fixing studs at 1200cc to the rafters then bridging between them close to the top (at a useful position), then fixing an in-between stud. More work, more wood. These studs will vary in height from 2.5m to 3.6m. This is the highest section. Studs probably 140 deep, to receive PIR, and for stiffness at this height. This is for the building warrant application, so isn't a terminal decision, but it would be nice not to need to change it.

Brilliant timing for this discussion. I am this very afternoon designing a section of our project in timber (partial demo and replacement). In ploughing thro the convoluted design guidelines I find the need to apply osb to the internal walls to use as buttresses, and there they are on the photo. Also the need for very heavy timber as lintels. C24 and min 80 thick, and that would increase for more snow or wind, and quadruple studs at the door openings (which I now know are called "cripples".) Can you tell me please, if not too much trouble The depth of the studs (and hence the insulation quilt) I am guessing that your osb being on the inside of the external walls is because the outer skin is the Gutex board as shown, which doesn't have the strength. Does that Gutex board get fixed as positioned, and then what outside it? Are these lintels a single piece of timber and what depth (Mine have to be increased to 220) I have another question arising but will open another topic rather than muscle in on this one.

Scary thought. And have the neighbours done it properly or just done it? Hence Engineer involved from early. Or if the neighbouring house has done this then forget it?

Correct if you can do it. But the north side intake is not going to help the south side heat build-up unless you can vent from that room. I have used this principle in very big sports halls, and it works by natural ventilation, bit in summer needs fans.

And be careful laying it down. Never on a corner or a surface that isn't flat. If it is real quartz then it has lots of planes of weakness.

Then he has probably bodged the whole thing. I had assumed this was a long-fitted toilet. The smell of blocked drains is distinctive and sort of sickening. Doesn't smell of poo but of swamps and festering stuff. My tongue is tingling with displeasure as I write this, so that may be a clue from the depths of my instincts.

What would the Egyptians have done? Firstly that trolley from b & q. secondly some rugs to slide it along or lay down without damage. thirdly lots of workers. If you have the last option all other issues are resolved.

I know Glasgow. Twice as many wet days as Edinburgh. The dear green place. Well positioned for when rainfall levels fall, and there is a water shortage in the SE. One thing that will not change is the height the sun goes in the sky. In most UK there is possible overheating in August, and a few days when it is as hot outdoors, and ventilation isn't the solution, until night time, when an air purge is useful. White or metallic blinds work fairly well....if they can be seen in a window, then that is some light being reflected back outside. 30% of 30% or so, but it all helps. as would some ventilation ....an opening window if that is not too old-fashioned.

So the hopper may be acting as a breather pipe. No windows near? so no problem.

Assuming the toilet waste pipes just disappear into the floor and it all works ok? What are the 2 pipes in the picture, into the hopper, draining?

Really the only way to control this solar gain properly is with shutters or other shades outside. In theory internal blinds and curtains don't work especially well as the sunlight has already entered the room. In practice of course they do work especially if you can use light colour to reflect some light back out, and enclose the space between glass and blind, so that some of the built up heat goes out, or at least stays there. The other solution that avoids air con cooling is simple ventilation. as long as it is cooler outside the temperature will be reduced. Air-con cooling shouldn't be necessary in Glasgow, and perhaps you can reduce the problem, and cost, these other ways.