WisteriaMews

When selecting our system I wanted the option to be able to use it with smart tariffs. Octopus seems to be the leader in this space so I checked which systems they are compatible with. We're a way of installing but I've specified a GivEnergy battery on this basis currently.

Based on Companies House data I think Build Collective are now in administration, hopefully no one has been caught up in the situation. (We ended our relationship with Build Collective not long after I made the original post.)

We're a bit complicated with a timber frame sitting on a basement. Our basement design has ended up a certain way through working with the structural engineer and a contractor to keep the cost down. MBC have their timber frame design and the way it transfers the load through the frame wouldn't work with our basement design per their standard details. They didn't seem interested in doing things differently and I didn't want to work so badly with MBC to try convince their structural team we could find a solution.

I'd love that to be the case, but if there are no experienced passive house contractors in my area what can I do? (Hence the post on the forum trying to find a suggestion my research might have missed.)

We have a timber frame company hopefully lined up (MBC weren't interested due to our foundation design). We're searching for a follow on contractor that will know how to install windows to a passive standard, wont puncture lots of holes in the air tightness layer and just generally buy into the concept of what we're doing.

Does anyone have any recommendations for passive house experienced builders that operate in south east London? We are hoping to issue our tender soon for the house we're aiming to build to a certified passive house standard. We'd ideally like a contractor experienced in the passive house approach so they are across all of the necessary airtightness and thermal bridging requirements etc.... I've looked on the Passive House trust and AECB websites, but south east London seems to be a bit of a desert for registered contractors! We have spoken to one contractor who has sent someone on the PH contractors training course, but they have never done a passive house project.

Just in case others stumble across this thread with the same question, I've been told by one of the wood fibre technical teams that there is some compliance testing taking place in September 2025.

We've been quoted a very similar price.

Not installed yet, but we're planning to use GSE trays to make the panels more or less flush with the standing seam The solar company have said there is no extra cost of the GSE trays vs clamps and rails to put the panels on top of the standing seam. We haven't finalised the tinsmith yet. We've spoken to one who has said they've worked with the GSE trays before so we know it's all doable. In theory a saving as there will be no standing seam under the panels. The tinsmith will have all of the flashing details to do around the GSE trays though. (I find somehow things are never cheaper!)

@SteamyTea from what I'm learning in the post Grenfell world you can't have a good idea like covering the wood fibre in intumescent paint. It needs to be actually tested and certified to be accepted. The tests cost £30k and there is apparently quite a waiting list, so you're basically dependent on manufacturers certifying their products and it doesn't look like anyone has certied wood fibre insulation yet. @gavztheouch we have bedrooms above the height where you have to start considering the fire regs. I wish we didn't but planning restrictions (we're in a conservation area) have forced us into a certain design.

@Iceverge we're planning a factory built frame by All Timber Frames from near Exeter. Aiming for a u-value of 0.1. Rockwool seem to have a intumescent cavity barrier certified for use with their rainscreen duo rainscreen product. If we can't find an intumescent cavity barrier certified for us with woodfibre then we may need to explore whether switching over will be possible.

@Mike we think it is possibly a UK requirement (post Grenfell) and not required in Europe. This is part of the problem, it becomes a bit niche when it is just the UK so there is no approved details. @ADLIan we're finding BCO won't give advice any more as they cannot act as designers, you need to present them with an option that they'll either approve or reject.

@Redbeard @SimonD Our planned build up is very similar to the one Simon linked to (image below), except we're planning a batten and counter batten before the external cladding. Our architect has taken the lead in trying to find a solution. They've been speaking to cladding suppliers and cavity barrier suppliers so far and drawn a blank. I've contacted Ecological Building Systems who market a timber frame build up similar to the image and they haven't got back to me (despite a few chasers) so I suspect they don't have a solution. We hadn't considered a render scratch coat. (Thanks for the suggestion.) I'll also check if the architects have contacted the wood fibre manufacturer technical departments and if not get in touch.

Are you planning to build the timber frame kit yourself? Or are looking for a company to install the kit for you? I would suggest sending your plans to MBC timber frames. They offer a free quotation service and will include the foundations and windows in the quote. This would give you a realistic benchmark for a watertight shell (without any external wall or roof cladding).

Our planned wall build up is a timber frame, wrapped on the outside with wood fibre insulation and then a ventilated cavity and timber cladding. We'll need horizontal cavity barriers and haven't been able to find any manufacturers who say there product is approved for use with wood fibre. Consequently Building Control won't sign off our plans. Has anyone recently built with a similar build up and found a cavity barrier approved for use with a timber frame covered in wood fibre? Thank you.