Gaf

Wasn't sure to post here or in ventilation - my main concern with airtightness is the heat retention as we have MVHR looking after the ventilation (as least that's my understanding!). Builder said that after the chasings are serviced (e.g. electrician does his thing), he uses a sand cement mix to fill in the chasings for airtightness. He doesn't use airtightness paint (e.g. blowerproof). I'd seen posts here stating that sand-cement internal skimming is a perfectly good airtightness layer, so would there be any drawbacks to the builder's proposed method for the chasings?

According to the builder, joinery, and our BS, the architect went OTT on the steel to cover himself. Builder and joiner said they've never seen that size of steel put in for that size of a roof.

Coming back to this. Long story short, only a small number of SEs available, quickest would have been 6+ weeks wait and sought €1k+VAT just to inspect the steel, wouldn't include inspection of anything else or do a walk through with us. One SE actually recommended our BS and said if our BS was signing off on it and said it was OK, then the SE said he would trust it. Our BS got the builder to supply confirmation in writing acknowledging they built it differently than the plans and that they were standing over the structural stability of it. Not perfect, and may not be what the more knowledgeable here would accept but we felt very stuck with how to proceed with varying levels of advice.

Thanks again for your post. Appreciate the advice from someone in the field. Just before touching base with the architect on this, the reason I was going straight for an SE is that there was an issue where seven dormer roof structures were built differently than on the drawings. There was a little kerffufle where the builder felt the drawings weren’t clear and the architect holding firm that they were clear (as you mentioned, I took a non emotional position and stuck to facts but I think events not of my doing has lost some goodwill from the architect). It was two days of work to have them changed back to match the drawings at the builder’s expense. The architect took the position that if anything is done on site differently than on the drawings then it is on our certifier now (our chartered building surveyor) to sign off on these. I believe I will just get this same response now from the architect, effectively “We designed it as A and your builder has done B. We’re not certifying the work on site so this is a matter for your certifier”.

Really appreciate your post. I’m on my phone so harder to get a decent response in but I’ll try (and try keep it concise!). Whole house is a new build. “Storey and three-quarters” was specified on planning. All walls (internal and outer leaf) are block. Outer walls are double leaf with 150mm cavity. This whole post relates to two rooms in particular (~10m2 and ~19m2) both with vaulted ceilings. These rooms are circled in blue on the attached (I don’t want to upload the higher res PDF drawings as the architects name is on them but can get higher res plans from PC tomorrow). These two rooms had the same construction drawing detail for their roof/ceiling. Steel beam as the ridge beam (attached). Builder has built both roofs differently than specified on the drawings. He has a timber ridge beam that as best I can tell is only nailed to the rafters. This timber ridge (sort of) sits on another timber, with this piece of timber sitting on the steel beam (close up photograph attached). The timber ridge beam is not fixed to the timber that it sits on, and this piece of timber is also not fixed to the steel beam. Builder has the steel beams sitting on slate shims, with the slate on padstones. The slates are not on the house yet. So far only a material looking black felt with what I think are counter battens are installed (attached photo). No wooden sarking board is installed. I can provide more specifics but don’t want to go OTT with detail (maybe I have already!). In terms of professionals involved: We hired a registered Architect (RIAI) to do our construction drawings. Was lining up an SE until the architect said our house design was not complex and he was qualified to design, specify, and sign-off on the structural elements. I have it in writing that he has formally given design sign-off on his drawings that include all structural steel. For Building Control in Ireland, three professionals are registered as being qualified for certification of the build stages (architect, engineer, or chartered building surveyor CBS). We opted for CBS as he is known to is, is local to the area, and helped a lot with managing the local authority for our planning permission stage. Likely now a mistake not to still get an SE involved. As you mentioned, we didn’t know any better but weren’t actively trying to skimp on this. The architect firm is very well known in the area so we felt we could trust his confidence on not needing an SE. I absolutely understand an SE may want nothing to do with this at this stage. Whilst I’m primarily concerned about the roofs on these two rooms I plan to ask for a full house survey so at least hope that would make it financially worthwhile. Fingers crossed. 100% agree, I’m not sure banging on the architect’s door about this is fair. If the builder thought the design wasn’t detailed enough to build it then in my book you make a phone call to get more detail instead of building it a different way. Bar asking to add in two skylights way before any roof work was even near starting, we have thankfully made no changes whatsoever to the house so any deviations from the drawings will be 100% on the builder. I’ll be pursuing the SE route and will be happy to pay their fee. In the interim, again really appreciate any steer on this. I’m particularly conscious the builder plans to start the slates next week and I want to have some kind of confidence asking for that work to be paused until an SE can inspect.

Called ten engineering companies in the area flagged as including SE. Three SE’s may have capacity to have a look. Rest are not taking on work due to being too busy, only do consulting, or only do design with no on site surveying. Awaiting calls back tomorrow 🤞

Sorry yeah that was scant on detail, wasn’t a great post. I can’t get better photos as that timber is up high and I only got those from strapping my phone to a stick. Roof only done a couple of weeks. Only the felt is currently on the roof (no slates till next week). No ceiling work done (no VCL yet) and just exposed at the minute. Windows are in. Timbers were exposed to the elements for maybe two or three weeks before felted. I can’t see if they’re particularly damp.

Not sure if I should have this in the "Damp" forum. New build house. Whilst inspecting some timber work on two roofs for another purpose, I noticed what I thought looked like mould growth on a small number of timbers. Google suggests some view this as a concern that should be remedied but others suggest this is typical enough for timber and likely occurred in the yard before it even arrived on site. Anything to worry about, or best left alone?

Cheers again lads. And 100% @torre I appreciate the info from everyone and don't take it as unnecessarily creating worry 👍 I got a visit to the site with the building surveyor. First thing he mentioned was the the size of the rooms meant, in his view and experience, the steel wasn't even needed and probably shouldn't have even been installed (one is 3.2m2 room, other is 4.3m2 room). His only gripe was wondering why it was installed if the timber ridge beam wasn't resting on it. He said best approach is to email the builder and ask him to confirm the roof is sufficiently supported so that I have it in writing, so if something happens down the line I'll have comeback. Was 50:50 about this and just thought why not just get it 100% now. Builder ended up arriving on site as we were looking. It had been blocked up in the interim so we couldn't get up to get a proper look. BS spoke to the builder for clarification. Builder said it was a slight bend in the end of the timber ridge beam that made it look like it's not resting on the flatter timber - he said his joiner/carpenter did it and told him it was resting on the beam. Surveyor seemed perturbed initially when querying why the steel was even installed but also took the builders word the timbers were in contact throughout. Only afterwards I managed to stick my phone on a stick and squeeze it up into the upper roof part and get slightly blurry images (attached). It looks like there's a few mm gap between the timber ridge beam and the timber lying on the flat near the end of roof (original photo end) but there's no gap at the other end (second photo). To date, there have been four 'issues' I've had to raise so far with all of them getting remedied - one was sizeable enough (two days work for a few men to fix but it was on site decisions being made instead of sticking to the construction drawings). I'm trying not to be that PITA client but I find it challenging when my own BS is saying it's OK. I think I'll have to put my big boy pants on and approach an SE before much more work gets done on site.

Yeah mate I really don’t understand it. At even my own basic level of knowledge I don’t understand how the wood over the beam has no function, it’s the only potential contact between the roof and that steel beam. If it has no function then that effectively means the steel beam has no function and that roof if being held up by the outer walls with no joists in place.

I don’t know what to think at this stage. Building surveyor came back. Has no concern with the slate shims as they are, basically leave them as is. Said the piece of timber between the wooden ridge and the steel beam has no function. Said the fact it isn’t clear whether this piece of timber is touching the ridge or not is nothing to be concerned about. Have asked for clarity over what he feels the beam is for then. Have both responses in writing…

Looks a bit like the architect may have expected them to build it something like this:

If I’m reading you right, he was an actual architect Architect (RIAI), not a technician, engineer etc. Am waiting in a call back from surveyor on it.

Architect has been good with minor queries so far related to certain detailing not included on the drawings (e.g. he specified ridge heights and roof angles but not wall plate height as he said that’s calculated on site). He’s kept a boundary on signing off on anything on site though as we didn’t hire him to certify anything and has (I think very fairly) pushed back on this being our certifier’s job now (building surveyor). Joiner said the collar ties have to stay because they’re needed for the worked needed for the insulation and air tightness. No idea myself on that…

Yeah I found lots of posts with slate recommended over other materials as it already has massive compression strength. Would you expect the slate to look a little neater than was done though?