Hilldes

Thanks PeterW and @markc . I've also been in touch with timber frame supplier (MBC) who will put me in touch with their joist designer - just to be sure I can reference if queried.

Thanks @saveasteading for the guidance. As you suggest, I'm not keen to get a structural engineer involved (from my experience charge high fees and deliver little of value). I'll try the timber frame company - they may have some specific guidance or maybe can pass me to the joist manufacturer.

I could do with doing a similar thing - but I have only single post joists at 400mm centres (don't have a 'spare' ?). The top and bottom chords of the posis are quite wide due to span - 145mm. Scenario is there is a stud wall running directly on top and parallel to a posi joist, need to drill a couple of 15mm holes to get services into the stud wall. I've googled and looked at NHBC, but can't locate any guidance specific to metal web/posi joists. The most direct in terms of advice is here (Professional Electrician), which states that no drilling is permitted anywhere. Can anyone share any official guidance that can be used if required with Building Control and Warranty provider please?

Oops, just watched the video again. Was supposed to close the flow gauges as each circuit was filled, but didn't. And I was supposed to re-open all flow gauges and return valves at the end and see the pressure gauge rise. Will open all valves now.

Thanks @Nickfromwales, I too would have expected each circuit as it was opened to apply pressure to the return pipe and both sides of the pump. I followed the procedure in the Wunda video, so closed the white decorators caps after each loop was filled - so now they are all closed. All the flow gages were left open as per the video. The mains hose pipe was attached to the top rail and the drain hose to the bottom rail (as per Wunda video). Ironically the pressure gauge is now reading 4 Bar up from 2 bar this morning ? and it has not been touched in the last 24 hours (no mains pipe connected in this time).

There is something beautiful about manifolds and regimented pipes ? I think the answer will have something to do with the mains pressure being applied to the top flow rail and that trying to push water in the wrong direction through the pump. But I would have thought the pressure gauge would get a reading due to pressure in the lower return rail when the valves for a given circuit are open.

…yet this morning the pressure gauge is reading nearly 2 bar - but has been disconnected from mains water pressure overnight ?

I filled and pressure tested the ground floor manifold at the weekend. It is a Wunda premium manifold with premium pump set. I originally planned to fill and pressure test the manifold and pipes before fitting the pump set - using the pressure test kit. Then I saw this video from Wunda that appeared to connect the pump set first and then fill and pressure test. Basically, the pump set is assembled as normal and attached to the manifold, but the return temperature gauge housing is replaced by a pressure gauge. The filling and purging went well, however the pressure guage did not move from zero except from a short time when it moved to 1 bar filling one of the last loops, then went back to zero. Can anyone think of a reason why the pressure gauge would not be reading? I've swapped out the pressure gauge and both show same readings.

Sealed in what way? The yellow ducting was put in before the pre-stressed beams went in - although not the pipe.

Thanks @Nickfromwales will check on the ventilated void position next week.

Bizarrely, if I interpret the Tracpipe document correctly that might be allowed. So in my case, it could not go in the void beneath the beam and block and it could not go in the structural toppling (slab) but it could go in the insulation sandwiched between them.

Thanks @joe90, is there a void under your house and is it ventilated?

Thanks @MikeGrahamT21, the plumber spoke to the Gas Safe technical helpline and another plumber that does a lot of new builds. On the Tracpipe page 66 "Installation of TracPipe® within a secondary containment We are sometimes asked for recommendations for additional piping (or secondary containment) to enclose TracPipe® when running through unventilated enclosures, ducts or voids. In the first instance we would always recommend investigating to see if TracPipeCC® can be used as an alternative solution or, if this is not possible, if the space or void can be adequately ventilated (see 8.8.3)." The void under a beam and block floor has to be ventilated, so I wonder if the plumber/Gas Safe are assuming the void is not ventilated, I'll check. For plan B, talking to the plumber this morning, there may be a way to limit the length of chase to run the pipe in the slab - by running it up walls in the timber frame and through the ceiling void (which surprisingly is acceptable). But looking at the Tracpipe text, any chase into the slab (which is a structural concrete topping above an insulated beam and block floor), this may not be possible either: "Pipework must not be installed in any location where, should there be a requirement to gain access to the pipe in the future, this could affect the structural stability of the building (for example within a structural screed or topping or within a structural timber floor)." "TracPipe® and TracPipeCC® must not be buried in structural elements of the floor, such as concrete slabs or structural toppings".

Plumber is on site and about to run gas pipe from plant room to kitchen island and concludes cannot run gas pipe under a suspended floor. Our floor is beam and block. I have run yellow 110mm yellow gas ducting from plant room to kitchen island location. Plumber says can't run any kind of pipe under the suspended floor (including Tracpipe) even though the pipe will be run in the 100mm yellow ducting. Anyone encountered this and found a solution? Only option I can see would be to chase out several metres of concrete slab (and under the stud wall shown in pic) in order to run the pipe above the suspended floor.

A quick update on threading pert-al-pert pipe through posi joists and fixing with spreader plates. Now completed the first section for real with loops pulled down between joists and not a single kink. Takes some time to plane the route to pull through and time consuming to complete the install. I did price up switching to Wunda over floor, but that added £5K and I suspect would not be much quicker in areas that require duo boards to be laid on to of Wundatherm.

Manufacturer spec says leave open to the outside for the V200 Energy "No sealant material beyond the dotted line": But differs depending on the type of window.

Some frames did not have recesses as such, so I set back circa 10 mm to make any non-straight runs of tape less visible. Other frames did have recesses - of circa 25mm width which needed to be missed and the tape placed on the wooden frame behind the recess (see pic above on V200E). I'm still deliberating how to seal the bifolds which do have a recess at the front that the tape would need to sit within (see pic below). I'm sure in practice the recess is deeper than shown in the pic and if the tape does not site neatly in the recess (i.e. parts in and parts out of the recess) we'll see a wavy line of tape as the recess is so close to the front on the frame.

Would you use tape for the orange section? The data sheets for the windows I have specify squirty cream (aka expanding foam) for the bit in the middle (assuming your pinks items are the airtightness seal). P.S. on the width of expanding foam tape, I used 20mm throughout, I think you may get a good seal with less, but with 20mm you can misalign slightly (virtually impossible to get a really straight run in narrow gaps). I think to some extent the gap size of the tape also determines the widths available (i.e. larger tape widths for bigger gaps).

Our steels at the glazed gables are portal frames - below in pink...

We have glazed gables, with tilt & turn doors, triple glazed alu clad. £3.3K each inc VAT, excl delivery...

I got 5 quotes and there was not that much difference in the prices.... I would have said go for fewer quotes as it is not just time for the buyer but also the seller. These quotes were though direct from manufacturers and it looks like even Velfac now no longer supply direct (rh2205's post), so with their partner/agent/distributor model it may indeed be wise to get more quotes.

Our Velfac windows involved dealing directly with the manufacture as far as I am aware. The first quote (contact via web) was May 2020 so policy May have changed since. Velfac don’t install and appear to provide details of the sale to a network of installation partners - we magically got a couple of quotes from installers. Our front door was via Kloeber which again was direct with the manufacturer as far as I’m aware. First quote also May 2020. Our roof lights are Velux and you can buy direct from their web site but we got them at lower cost from Jewson. We self installed all our windows.

Thanks @willbish will try your technique.

Thanks for the tips and pics @willbish. We had a play that involves a similar technique - thread the pipe straight through the line of joists in a straight line then withdraw a loop down a gap between two joists. See pic. This worked really well - the pipe was on the decoiler outside in the sun on a hot day. Will try for real in a few days (need to complete fire protection lining of the plant rooms - a separate thread). Plan will be to withdraw one loop then secure in spreader plates from below before pulling down the next loop. Then cut pipe from the decoiler and thread through for the return back to the manifold. Hoping the warm weather will return.

Thansk @gravelld Can't see that particular product. Is it this one which appears like compriband? https://www.iso-chemie.eu/en-GB/sealing-solutions/sealing-products/multi-functional-sealing-tapes/iso-bloco-multi-functional-tape Or this one which appears to add airtightness..? https://www.iso-chemie.eu/en-GB/sealing-solutions/sealing-products/multi-functional-sealing-tapes/iso-bloco-one