Great_scot_selfbuild

I have ‘binned them’ for exactly that reason, confirmed by the fact they couldn’t explain how they had calculated it. just about to post a new thread with some different but similar queries.

circuit vs zones.yes, aware of the difference which prompted this thread - I was surprised the company had only recommended one circuit for a rather large zone. We don’t have a design yet - that company just gives an initial quote but then you have to pay for a design (I’ve found someone else who I’m waiting on a design from now). Pipes are only in the coloured areas - i.e. not under permanent fittings such as bench seating and island. I was expecting multiple loops simply because of the pressure losses (building being 18m long means a single circuit would be huge!) We’ve had a full part O modelling done, so all good for the solar aspects. You’re correct - the X is a washer & drier stacked.

Thanks @JohnMo I am inclined to go for single zone, but we were just hesitant about whether the living room would heat up too much (no opening window - relying on MVHR). Yes, it’s a big hall, but that ship has sailed into the distance now, and it does feel like a good space.

Happy New Year all, I thought I had a good solution for my UFH, but having re-read the quote (111 sqm, 2 zones) it only specifies 2 circuits. I was happy with the quote (£1083) but I’ve not yet paid the £120 for the UFH design as I have heard of others offering this as ‘free’ (though they will undoubtedly wrap the cost up in other ways - such as another quote I had for £1600 with a free design included). Another reason was that when I asked how they only calculated 2 circuits, it turns out this estimate was based on their simple tool that uses the total sqm and when I questioned about pressure loss over a long circuit, they clearly didn’t know (could have just been the sales person lacking knowledge). I had intended to use LoopCAD to do my own checking but I now find that it only works on Windows OS (yet another reason for me to be frustrated at committing to Apple…). So… I’m looking for some help to check what i should be expecting from a UFH design, advice on different circuit designs (spiral / serpentine etc.), and any recommendations for a design or design & supply service (I’ll be installing myself). Thanks 😁

I’m in this position too. I’m certain I'm being pushed quotes heavily oversized, and I don’t want a system that keeps turning on because it’s not been properly calculated and sized. I just have very little time outside of work to do it whilst also keeping tabs on the work being done (where I keep identifying issues that need my attention immediately 😭). following, and will update as I progress myself.

Do you get the previous PC to sign off for the work up to that point? If I brought in another PC, and they were expected by Bldg Ctrl to sign at the completion, they would surely not be expected to sign for the earlier stages of work? (or if they are, how would this be managed? have you had to do this, or seen it done?)

Does anyone have any experience of this, or advice please?

Just thinking through options - we've had a principal contractor from the start, whilst some specialist contractors have come in for different elements of the build, the PC has remained constant. If we get to a point where we look to finish the internal fit-out ourselves, how does the PC role and (specifically the Building Control Principal Contractor sign-off work? I'm aware that the PC definition for CDM and Building control uses the same term 'Principal Contractor', but has a different definition and responsibilities. My main focus is related to the PC Building Control sign-off, though I am interested in the CDM aspects too. Grateful for your experience & thoughts. I'm trying to make sure I have a clear contingency plan in case we a re finishing the build and fit-out by ourselves.

@MikeSharp01 useful thread - we're going through this atm. The plan had the windows above 800mm, but because the timber frame designer didn't mention he'd moved the windows down when a deeper rafter was installed, we've now got a design change / compromise with the windows being down at 650mm!! (apologies for the rant...)

@alexo I know this is an old thread, but I have exactly the same situation and have internorm windows being fitted. Could you possibly upload some photos or a video of this turn restrictor showing how it works? (hopefully you'll see this...)

Buildhub for the win again! Thank you @Nickfromwales & @Kelvin

Thanks for the advice @Nickfromwales. Can you explain about fitting the trailing socket - I can't see or find any details about what the end fixing is on the Defencer lights (here - https://www.screwfix.com/p/defender-22m-led-festoon-lighting-chain-10w-8000lm-110v/4693T?gclsrc=aw.ds&gad_source=1&gad_campaignid=22605815174&gbraid=0AAAAAD8IdPzAOvlf0h99fWKcI5vmuavk_&gclid=CjwKCAiAlMHIBhAcEiwAZhZBUq7WHfNLT9emuDmtdSAF-7MrzRbsVmZfgfMe9Fbjf8cNGA6BSrjFxRoCjDcQAvD_BwE) Is it as simple as wiring a 110V socket onto the end of the festoon trail? (couldn't find out much about the end of the festoon lighting).

I'm looking to get some 110v lighting. Our timber frame is going up quickly and soon (in addition to the days getting shorter), the build team will benefit from lighting inside the frame - especially once the roof and upstairs floor boarding goes on. I'm looking to buy some (rather than leave it to the team to provide their own) as I know I'll need it for ourselves anyway. I've come across quite a few different types and one of the versions I wasn't aware of until just searching were the daisy-chained LED bulbs, which I thought could be rather useful especially once internal walls are covered. Here are screenshots of the examples I'm coming across (just examples, I've not gone through the specifics yet - just wanted views on what type/style/power rating people have found good or bad). Image of our site to give an idea of how shaded we are - hence this will really start to make an impact. IMG_5224.JPG IMG_5151.JPG

They don’t have to be. We have a steel ring beam and columns - they have 2 coats of zinc oxide and 2 coats of bitumen. Galvanizing would have added a lot of time & many thousands £££

This is (slightly) encouraging. Do you have any photos of this by chance? Was the internal face of the steel covered or were both sides left visible/uncovered?

Yes, ordered. Frustratingly, there were many design discussions where this should have been raised by those who do it for a day job (and were being paid to…). I’m more than a little angry😡

The original design was for the column to be inside the windows, but the timber frame structural engineer stated that it ‘had’ to go in the corner. TBH this really hacked me off that they weren’t able to calculate a small cantilever for the loading. Ultimately I trusted the collection of design professionals involved in the whole build / design (and I had them all join joint design meetings). I’ve got to the point where it can’t be changed now, and in the general scheme, we can come up with a solution I expect using the Aerogel type of product. Yes, it’ll still have the steel passing through, but the internal being empty wouldn’t help. Thanks for the link to an earlier thread - I’ve only read part of it so far, but it’s already giving me confidence in finding a solution. TVM!

We have steel columns (250mm square cross-section) in the corners of our timber frame with steel lintels which allows for glass on 3 sides. The steel is visible inside & out, and although I’ve been asking for the detail for some months, only now that we’re very close to installation have I established that none of the design team (Principal Designer - architectural designer), Timber frame manufacturer (designer, structural engineer, production manager…) has mentioned it until I have pointed out that there’s no insulation in it (on the drawing). The drawing I'm concerned that there's been no design discussion about how they will be prevented from becoming a very significant thermal bridge. Cue silence… In the interest of now finding a solution rather than playing a blame game (adds no value), I’m seeking this group’s thoughts and experience. One suggestion has been to drill holes to inject expanding insulation into the column, with holes positioned in line with where the window frames will go (this method would need more than one hole to get it in far enough and fill the full height; the holes could be subsequently weld-filled afterwards, and this would obviously need approving by the structural engineer). AAAAARRRRRRRGGGGGHHH!!!! So frustrating….

Do you mean upstand above the flat roof? If so, there will be a lip of some sort for the guttering. With your warm roof, did you just take the wall insulation up to the underside of the roof board (rather than this drawing showing it stopping at the underside of the joists)?

I had wanted to go back to option B, but the flat roof and ventilation gap will be a paint to sort, so I’m thinking the option A - I think it’s just a case of taking the wall insulation up to the top. Worth adding that I only received this warm roof design earlier today (5pm) and haven’t yet had a chance to ask him this question - but it will be with him tomorrow!

It doesn’t feel like I’m getting very clear advice from our principal designer. Any comments on these options? Thanks in advance.

Which is best and why, or is there nothing in it between 11mm OSB and 12mm Medite vent panels for the roof sarking. Our roof will have 350mm of warmcel between the rafters (U=0.11), with 50mm air gap above the sarking by means of battens & purlins supporting a corrugated steel roof sheeting. The original scope of the timber frame had 11mm OSB listed but the designer has specified 12mm Medite vent and so I’m being asked which I would like. The price difference is £10/sheet, and we need 164 sheets, so £1,640 uplift for Medite vent. Have any of you used both and what would you go for and why? We’re going for quite a high spec performance build, and have prioritised the fabric of the build. If there’s a material benefit/value to be gained then we would consider this extra cost, but we can’t afford to do it just on a whim. Keen to get the experienced view from this group. Thanks in advance…

Any recommended tools / method for the UFH layout/circuit designs?

@BartW Thanks for creating this thread - having read it now, I think I’ve saved myself a lot of work being led down the comfopost path by some M&E suppliers. I’m becoming less trusting of the technical competence of some of the companies I’ve reached out to and am finding myself doing so much double-checking and calculations myself, I’m very interested in how you’ve gone about designing the UFH / ASHP / DHW system. I’ll be starting my search for tutorials and advice on how to go about this, but would welcome any advice you can offer?

@JohnMo amazingly helpful and clear - thank you!