All Activity

Imagine concrete but the aggregate is like pumice or volcanic stone, very hard but lightweight. they use it a lot in void filling after pipeline work. it can be cheaper and easier to muck away everything that comes out of a trench and import in all the backfill because it doesn’t need compacting, it just pours and forms into all the irregular shapes of the hole.

Not something I'm familiar with.

I thought there are a few void fillers that don’t need compacting and are very light and can be pumped. the days of barrows and compacting in layers has gone for these large fills.

Sounds like they are trying to prove exactly when the property was completed. Many policies don't cover houses undergoing building work.

This is the bit I had picked up on. Of course they may have filled in the stairwell, but the manhole cover suggests maybe not?

Solid timber studs, or I-beam (which latter builds in a degree of thermal bridge mitigation)? BTW, if you have not 'done' this level of building before, treat with some caution claims that designs or execution have 'got rid of the thermal bridges'. Generally, while you can make them 'less worse' ('mitigation') you can't necessarily get rid of them without removing the element altogether.

A coal hole? It would probably be difficult to fill and compact after the first few feet.

Certainly sounds like full mitigation has not been implemented. If you (OP) know nothing of SAP you may need to try to find a good independent who can do the appraisal of the original SAP report. ( @saveasteading has posted as I write. Have not read his post yet). *Have now, and agree with it!

He says you've failed but doesnt know why? He put the numbers in. It doesn't sound like an expert, just someone with a licence for a sap spreadsheet. I've come across one such. He wasnt interested in the reality and just wanted to enter conservative defaults. Your construction should pass but tell more. Insulation spec in floor and roof?

@saveasteading and OP, I took it that rudimentary access exists from outside, (hidden under a manhole cover) so my musings assumed that full access could be re-instated temporarily. If this is the case the residents moving (everything) out may not be completely necessary - just a few days (weeks?) in a hotel for the 'worst of it'. Dunno. OP, any more details?

No need to shut off the water

Simple can be elegant. The trouble is the method. Imported stone ( a lorryload) has to be placed in the basement and thoroughly compacted. Where would it be stored? That mean breaking out the floor. Would the stone all be barrowed in? Then a new floor. So that does have the advantage of simple support to your floor and added lateral stability. You would have to move out for a month minimum. Another easy solution might be to support the existing beam. A central prop means that the beam only gets 1/4 of the current bending. Or a masonry wall all the width, or a new beam. All needing foundations. Not quite as disruptive but still a month out of the house. Gut feeling £50k including fees and unknowns. Lawyers will take more than the Engineers. 25 leases, £2k each. PS. On second thoughts there will be redecorating, accommodation and likely more that we don't know about. For discussion say £100k = £4k each. Would they all contribute or some not be able to or want to?

We aren't using a timber frame company. My husband is a carpenter and will be making the timber frame himself, mostly onsite. He was a contracts manager for big builds. But never got involved until after the design stage, when he got handed the drawings and instructed to build the building in question. Which was mostly commercial properties. He stopped working for them 3 years ago and went self employed doing small carpentry jobs in the building game so is a little unfamiliar with new building regs. We've only just given the sap assessor the spec of heating and hot water etc. so have only just found out that we have this issue.

I know someone who used expanded clay fill, then concrete slab with UFH. It was a considerable depth. You will need a SE input obvs.

What is the assumed U value for your windows and doors? Lots of glazing is different things to different people and can make a huge difference to the heat loss. I would go through the SAP report line for line to see what assumptions have been made, sounds shite in shite out to me somewhere. Post your report

If the cavity does not need ventilation you could fit a DPC cavity tray around the base of the plinth bricks linked to the inner leaf and fit the mini weep vents at 900mm centres.

To take a few points from posts above, firstly you (the leaseholder 'collective') need to appoint a SE with the remit to clearly establish the issue and to make recommendations for remediation. As @saveasteading suggests, rust is not (necessarily) equal to disaster. This needs to be an invasive inspection by someone with the whole picture. We have the Professionals' opinion (Doomsday scenario) but no apparent assessment of the immediate issue. For example, if an inspection of the beams found that rust was bad enough to weaken, but not catastrophic, then that (a) supports to temporary propping suggestion and (b) may suggest that breaking the span - permanent props on footings/mini-piles, maybe - might be a feasible 'treatment'. All of this from someone who is most definitely not a SE!

I've recently used this site ( https://builderscalc.pro/ ), to spec out and price a couple of jobs (for painting and mulching - so, simple and basic tasks), and it looks to be pretty close, but I'm unsure of its overall accuracy. Have any of you guys (and gals) used it before, and have you got any opinions on it it??

The details supplied by @G and J quite rightly say 'For discharging water from external walls', which is what I have always understood. How many weep-holes would you need to equal the cross-sectional area of just one 'ordinary' air-brick? AI says: For most standard brick veneer or cavity walls, building codes and masonry councils recommend a weep hole cross-sectional area of at least 100 mm² to 250 mm². [1] A search for 'equivalent area of 225 x 150 air-brick yields the (AI) response: "A standard 225 × 150mm (9× 6in) double air brick provides an equivalent ventilation area (free area) ranging from 4,300mm² to 18,000mm², depending on the material and the design". We appear to be comparing apples and... something else.

Thank you everyone, for the feedback!

I am sorry you are having this faff. As others have said, the dwgs may enlighten us a bit. Lots of glazing = lots of potential thermal bridges at the structural opening, which could be mitigated well or badly. There may of course be plenty of other reasons for the technical 'failure', but the openings would probably reward good scrutiny. I have not 'done SAP' for some years but surely your 'calc man' can offer some more insight. 'Because of possible cold bridging' is a pretty wide field. He's done the input. What are his suggestions for mitigation?

If you have lots of glazing I would not be looking at the lower end price wise.

Only one basement - the building was mapped using radar. Yes the liability extends to the whole building under the lease so all leaseholders will need to contribute. The initial advice from a firm of consulting engineers was very brief, virtually along the lines of "the beams are severely corroded and should be provided with temporary support immediately". They obviously weren't asked to suggest remedial works. The building and presumably now the basement is owned by a management company which in turn is owned by all of us 25 leaseholders in equal shares. It's down to us. The previous managing agent (part of a national property consultancy) basically told us all at a meeting that the building was worthless. When a couple asked what that meant for their mortgage and investment in their home the advice was to "hand the mortgage company the keys and default. You'll only be credit blacklisted for about five years...." The company then announced it didn't want anymore to do with the building and resigned their position. As far as we are aware only this particular flat is affected as it sits entirely over the basement. Personally I'm not entirely convinced that mass fill isn't an option. The live loads from a domestic floor are small, the dead load from the concrete could be reduced by using foamed concrete and I would have thought the total distributed load across the existing basement floor and the ground below would be well within the ground bearing capacity. I'm not wedded to that approach, I was just gaining other opinions to test my theory. I just want to be sure we are not being led in a particular direction to suit a single beneficiary with the additional costs of that being carried by the majority.

We used these. Didn't mesh as will "deter" larger insects, not sure would stop determined ants but 🤞