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@marmic I had to order undersized windows from 21Degrees to get the cill falls. I have a fully-built 485mm wall thickness and the structural openings in my timber frame are flat. If I place the windows centrally then the cill needs to reach 100mm plus 30mm overhang, leaving me with 6mm to pack (and taking that off the window manufactured height). What are other suppliers doing differently to avoid this? Providing a deeper bottom frame?

Note that the lower splay results in reduced insulation at the base of the Velux so I’ll using extra low conductivity PIR here instead of the high pressure pumped cellulose.

And it’s done 😊

Wow, a month already! Happy to meet up again.

Yep, splays are definitely an issue for us as the roof is 400mm thick.

Hi. After lots of advice here I've decided to stick with Velux for my roof windows. I'm trying to position one of my windows - RL04 - over the bed in our master bedroom but space is looking tight to the ridge and valley. How close can I go? The window could be the MK08 (780x1400) or MK06 (780x118). Note, I'm aware the structural opening is wrong - just caught that mistake! Should be width +60, height +45. @JohnMo I feel certain you know the answer to this one!

@Andehh Also interested in your source for blinds please.

Rationel were the cheapest of the suppliers we explored but I dropped them very quickly but only because of their window handles 12 months later and I have a longer list of reasons. I don’t understand why MBC promote them.

It’s certainly been challenging

Me too. There’s a layer of DPM to go across the insulation before the concrete (blue dashed line) so that should stop any concrete penetration. This is my air tightness layer as well as it laps over the upstand and is taped to the walls.

The idea is that the XPS upstand provides the former for the inner beam.

@BotusBuild I’ll ask. This insulation will be covered with DPM and there are complete layers under the made-up layers so I’m not entirely sure I should worry about them. @Redbeard that was my immediate reaction but now I’m wondering if I’m being fussy when in practice this reuse of off-cuts is just efficient good practice. There are two layers of steel mesh and 175mm concrete on top so perhaps not structurally relevant?

Nope. Those are for forming the outer ring beam (needed for a brick plinth) in place. The house frame sits on an inner ring beam.

My insulated foundation is almost ready for steels. What do you think? Lots of gap filling with off cuts going on.

FYI, I understand Norrsken have been bought by Viking now. Sales guy was fine with me, very responsive and knowledgeable. Ultimately it was the product that let them down. Weird how we have different experiences, feels like luck of the draw. Never came across Nordica! 21degrees have been good though also had pricing errors. It pays to look very closely at everything. Also have thick walls. They did tell me to reduce the frame height to allow for packing to create the fall. I didn’t think to ask them to increase the frame base height! Packing ranges from 6mm to 15mm depending on wall position. They offered to install but the travel distance made them £2k more expensive than a local installer. I might regret that saving if the windows don’t fit.

Exactly!

Yes, totally agree. I can only hope that the greed drives the industry to retrain and retool over the long term so that when the bucket is empty there's enough momentum to sustain the change.

I think this is what's galling me. I can buy the ASHP and tank for £5k. Add your £1.2k and I'm not far off the £6.9k the installer wants.. after the BUS grant. So I can only assume they pocket the grant as pure profit. I guess the sums still work for me, and I get a heat geek registered installer with service guarantee and less of a headache... so this is probably still the way I will go.

Maybe @Beau, though it's really hard to compare. My quote is £7k less but does not include rads and plumbing. Do you feel the extra work was worth £7k?

I agree with your point @Gus Potter I'm writing work packages at the moment and trying to paint as clear a picture as I'm able. I'm hoping this reduces the unknown details that cause the vendor to layer on contingency costs.

Mine is a new build. Just getting out of the ground so no plumber or sparky on site yet

@JohnMo That is so tempting, really.

I went for 21 Degrees. Other than Internorm they are the only vendor offering double weather seals on windows and doors. Unlike Internorm they also offer inward and outward opening doors. Norrsken were a close third but their doors only have single weather seals. NorDan likewise. Rational were good value but a step down in quality.

I posted my question to the FB Heat Geek group and two installers said they’d expect to charge £10-12k for the job before the BUS grant. Seems to be the going rate so at least I have some grounds to push back on my installer. He does seem to know his stuff though. I could go down the umbrella scheme route too. Where would I find such a scheme?