George

The IStructE have a 'find an engineer' service. An IStructE member is a pretty safe bet as the barrier to entry is a tough exam! https://www.istructe.org/find-an-engineer/

Just needs repointing. Access is always the tricky part of these jobs.

Yeah, so a modern cavity wall differs because the bricks and mortar will be less porous than older walls. They are also usually as least partially open at the top with the wall plate being connected on the inner leaf, meaning the cavity has some pathway to the outside world. There also won't be any sort of tray or weep holes in OP's wall so keeping the existing air vents is a sensible precaution. Lastly, if they are insulating internally, having a high level of ventilation in the cavity will keep the moisture gradient, drawing any water vapour out and away from the inner leaf.

As others have said, leaving the outer leaf vents open will allow for stack ventilation of the cavity. The ventilation pathway is for the outer leaf only, through the lower vent, up the cavity and back out again. The inner leaf can safely be sealed up and insulated internally.

They need to be left on the outer leaf but can be blocked up on the inner leaf.

Almost that. The red square links should extend to the top face (the lower mesh just gets snipped when it clashes). The concrete chamfer on the underside is just fill, it isn't really necessary in domestic scale loading for a structural role.

Unless you have ground investigation information, it can only be a specification based on informed guesswork, not a 'design' as such. For a that best guess for traditional foundations (concrete strip or trench) I'd maybe charge a few hundred pounds - basically looking at what information is available on the British Geological Society, maps and borehole data, specify minimum width and depth of the foundation based on provided loadings and any tree influence zone. (edit - plus reinforcement design for pads etc) Because traditional foundations are specifically covered in the Building Regulations, the main person will ultimately be the Building Control officer. They are able to instruct wider or deeper foundations within the limits of the Building Regulations. Thankfully they should also have local knowledge of the ground. (edit - but they won't do the foundation set out for you especially with an oak frame with point loads to consider) They might say traditional foundations are unlikely to work. Then other common options for domestic construction are rafts or piles. For a relatively straightforward reinforced concrete raft foundation, I'd be looking at best part of a thousand pounds, mainly because the drawing work is more intensive. If it's pile foundations then you are best going direct to a specialist contractor who can do the design and install.

If they are truly solid wood, as a natural material they are liable to warp especially if not stored in ideal conditions. I would imagine no luck with Howdens, although you might be able to get touch up paint. Carpenter time will run into a chunky bill, but they're there anyway doing the fitting.

Slab drawing appears to show dowels, and friction alone would do most of the work. Check with your SE but an additional steel would be overkill I think.

Lovely neat job! I chuckled at 6 weeks though. While it does take 7 days for concrete to reach a decent proportion of it's design (28 day) strength, you'd have been OK just leaving 48 hours between working on adjacent pins, and you could have done hit & miss pins at each end, so long as 25% of the length wall wasn't simultaneously undermined.

If the joist directly above is continuous and supported on either wall then the post is probably just there for handrail support. If you have a SE engaged they could do you a quick calculation to double check for a nominal fee. My only slight concern is that these would usually be doubled up as a trimmer, and as @markc said, this may introduce a slight bounce in the floor. But still, unlikely to be dangerous.

We fill our homes with flammable things, the structure is worth protecting, but only for as long as it takes to escape. The only other approach is a sprinkler or misting suppression system, but you will be looking at substantial investment and ongoing maintenance costs - likely more than decent insurance.

Chalk doesn't necessarily rule out clay (broadly speaking there are four types of chalk, going from A to D, which D effectively being silt, i.e. clay). Would look different to Marl / mudstone clay. Can't remember the susceptibility to shrink/swell, though. Have a look here if you want to find what soil type you are likely to have : https://mapapps2.bgs.ac.uk/geoindex/home.html?layers=BGSBedEngGeol,BGSSupEngGeol,BGSEGFSReports,BGSUSAReports However - as others have said, could well be a copy and paste detail. Not the worst crime but your SE should be able to clarify for you. You can change the TOC level as required, so long as the thickness that remains and the dimensions of the step meets the general building regulations requirements for steps and the depth needed for the anchors. If there's a significant cost saving then I would certainly do it - just run it past the SE. The architect doesn't need input on the foundations. As already said, the frost depth refers to the formation (bottom) of the foundation. If in non-shrinkable soils this is typically 450mm in the UK. (the 900mm minimum for shrinkable soils is not related to frost but to water content of the soil) Mass concrete foundations are wonderful simple concepts - you are just replacing the higher level soil which might move around due to water content and frost with concrete which won't. You just need to make sure they are wide enough and thick enough to distribute the load on the lower level soils.

Where are you in the country? Why don't you think there is clay? That detail is definitely assuming there is clay! Purpose of the claymaster (and the 150mm void) is to prevent shrink/swell behaviour (aka heave) - governed by the clay content and plasticity - from pushing the foundations and floor around. Yes. There is a minimum thickness of concrete you need. Usually for mass concrete this is simply the projection from the edge of the walls or, say 300mm (it is a bit more complicated but that would be OK). However in your case you will need to consider the minimum thickness for the resin anchors for the ICF reinforcement. Sounds like a detail the ICF supplier should be able to readily give to you.

Now the RHI has gone, buying direct is more appealing. The £5k grant can easily just be gobbled up in the overheads of a specialist company. I paid £11.5 for a 16kW system with all the internal tank and install. But that's all coming back as RHI payments (£2.5k back already) so just paying for the inflation.

Any with a door ice maker / cold water dispenser are basically putting a hole in the freezer door.

I was told that even a layer of paint will help seal the blocks and mortar. not sure how true it is but I did put some on before the plasterboard went up. However as it was an extension it didn't really matter compared to the rest of the leaky house.

2 options... Drive piles (eg fence posts) as either the permanent wall or as a temporary retaining wall to allow you to lay blocks. Or just dig back in narrow sections, say, 500mm or 25% of the length, whichever is smaller, at a time to limit any loss of material. What I would not do is just dig it all out as you would probably undermine what the office is sat on.

I've picked up some premixed tubs from here: https://www.traditionallime.co.uk/products/hydraulic-lime-products/natural-hydraulic-lime What you will likely want is natural hydraulic lime, NHL3.5. Just briefly, as the terminology is confusing: Natural hydraulic lime - lime which sets in the presence of water. Comes in 2MPa, 3.5MPa and 5MPa strength. It's breathable, repairable and compatible with most old buildings. 3.5MPa is the most suitable for most things. Non-hydraulic lime (lime putty, fat lime) - lime which sets in the presence of carbon dioxide. This is a weaker mix and requires a bit more specialised knowledge to use. Only reserved for very delicate heritage uses, especially in mortars but is used more often in internal plasters. Hydrated lime - lime which has been mixed back with water and is used as an additive with cement. It won't set on it's own and won't make lime mortar.

Think I'm going to put in a air to air heat pump / air con in my garden office and just go sleep in there during heat waves. Climate change resilience!

What was the outcome of this? My thoughts are - that without seeing it, the SE will say RSJ because that's what is usually needed and no point saying it isn't! - a single coach bolt just makes a hinge

If it's a ground bearing slab then what is under the slab is just as capable as taking the load. It could be slightly less convenient as it may want some additional spreader plates (for example, thick timber sections) to avoid digging in. But it isn't a show stopper by any means.

You'll need to post some pictures/drawings. You may need to get a structural engineer to do a quick design.

There is a minimum of 50mm on each side (so wall thickness + 2 x 50mm = 500mm) The SE's width will be based on loading and [assumed if no GI available] ground conditions. Going wider is no problem.

In terms of the design, this is the BRE standard solution for garden retaining walls: https://imgur.com/a/LJAP6pV You need about 1800kg of ballast per 1 cubic metre of concrete and (depends on mix strength) about 250 to 300kg of cement. Using the foundation dims on that detail: 0.5 x 0.3 x 18 = 2.7m^3 of concrete Which would take about 5 tonnes of ballast and 700kg (28 bags) of cement. Not allowing for wastage and the extra sand and cement needed for the mortar. Handy link: https://builderhq.co.uk/guide/concrete-mixing-guide/