BotusBuild

Just got this nugget back: However, for the size of cylinder that you require, it would need to go onto a much larger heat pump so that it has the capability of heating it. Do I smell BS?

Seeking feedback. I used the JHarris heat loss spreadsheet. The worst Total daily heat loss power for mean minimum OAT that I could get was 3.246kW. That was reached by erring on the side of caution with all the input figures but being sensible about it. I have informed Alto that the heat emitters would be UFH, and we would like a 250 or 300L hot water cylinder. I sent them the spreadsheet I had used so they had all the same input data that I had used. I just got back the quote and a performance document, the latter which makes interesting reading: Total Design Heat Loss - 8.53kW Design Flow Temperature for Heating System - 50C Design HW temp 55C with a reheat time of 1h10m I can live with item 3 although I would likely run it a little cooler (45C), but item 1 and 2 have me baffled. I have gone back to them and asked to see their detailed calculations that led them to the 8.53kW heat loss figure and I have asked why the heating system flow temp is at 50C FYI - they have specified a Mitsubishi Ecodan 11kW ASHP and 250L cylinder. Observations?

Worthy endeavour IMO What is they say, Every Little bit helps.

Used ones on eBay, or

Small round topped kerbing (sometimes called round top pin kerb) between the driveway and the gravel, installed so only the round top is above the level of the driveway - probably won't stop all of the gravel migration, but might reduce it.

of the where the beam extends out beyond the external wall? How about a picture instead? 🙂 The blue circles are where the two I-beams go through the wall. Everything in the direction of the arrow to the right is now warm roof (160mm PIR) - correction, the warm roof is above the I-beam that runs up and down the picture as well and up to those wooden frames on the left.

Belt and braces I can appreciate - hopefully we'd have escaped the house before those I-beam give up 🙂

I understand. But there is nothing technically wrong with what I have drawn?

That would mean doing that across the whole ceiling (about 50m2). The rest of the ceiling apart from these two steels is not a cold bridge.

John, With a larger R-Value surely Aerogel is doing a better job than PIR for the thickness at reducing the effects of the cold bridge. As I said we don't necessarily want to make this false joist too deep a feature.

I see what you mean. I can understand why they didn't get fitted 🙂

PDF of the same diagram Aerogel for roof I-Beam.pdf

TL;DR - Does the aerogel setup in the diagram below make sense? Long version scene setting ramble before you get to the diagram: We have 2 large I-beams each 160mm wide that support one part of the roof. On top of these I-beams is a warm roof setup, on top of which will be a green roof. One is 7100mm long, the other is 6200mm long. The bottom of each I-beam is flush(ish) with the web joists that hang from them. Unfortunately, one end of each beam protudes through the external wall as a 2000mm cantilever support to the roof. This obviously forms two nasty cold bridges which we are doing our best to now mitigate. Between the joists we will be packing with something like mineral wool to stop the heat getting to the joists through that route. Under the I beam, we've decided we will "make a feature" and create a false joist, but we don't want it too deep down from the ceiling. This will also partly assist in breaking up the very large open plan space. So the plan is to put up some aerogel (probably 10mm thick) supported by some PIR, then the plaster board will go round the whole lot. Constructive comments welcome 🙂

Thank you

Totally agree with POV.

Zak, I think the sincere opinion here is that quote is too high. Only you, and your family, can decide on what you must have, what you would like to have, and what you can without in order to remove things ro reduce the cost. Or, and what seems to be the considered best option, rebuild to the proposed footprint. It will be simpler for any builder and therfore be a better final product. It may cost a bit more to do, but extensions and additions are tricky and prone to introduce problems that you could spend years rectifying. Do yourselves a favour, look seriously at the demolish/ rebuild route

A brief outline of what you are asking them to do, and some pictures/plans, would help us to form an opinion 🙂

FYI - if it is Nudura, they will only "warrant" the use of Dryvit. Both companies ultimately owned by the same group.

John - don't worry 40mm out of 360mm will make an insignificant difference.

I would ensure you have any pipes or conduits in place but not trimmed all the way back (do that after the tiling) Fit your toilets and pedestals after the tiling. If they get changed in the future you won't end up with holes in the tiling where you don't want them.

Or does this help - https://www.mycarpentry.com/roof-pitch-calculator.html

@flanagaj, To answer your question, you already have the formula in your photo above. You already seem to know what x and y will be in that diagram from what you are saying in your messages here. So working out that angle should be straightforward (unless we are all missing something). However, you'll eventually work out the angles and lengths, do the birds mouth cut, install your ridge beam, cut your rafter with the calculated lengths and angles and then find it doesn't fit as snugly as you hoped. It's a building materials thing. It happens all the time. What @joe90 says above is the way to go. If you don't want to use then use CAD - Cardboard Aided Design - a piece of scrap cardboard, marked up against the fitted ridge beam, then transfer onto the rafter before cutting.

? is the length of the top edge of your rafter. Whether you have a 6" or 8" deep rafter, the top edge length will always be the same. Then cut the ends of the chosen rafter to the correct angles to connect to the ridge beam and where it rests on the top of your walls

👋 🤣 You can get flexible versions of those - I have these already fitted. Happy to come over and help design it.

I've been cutting that rigid ducting recently - about 8-10 times so far with an angle grinder and cutting disc, with a couple more to do. Believe me, you do not want to go there. The people doing the design need to know the orientation of your joists, and what they are made of so they understand what is possible. Insist on NO RIGID DUCTING. I actually ended up telling BCP where the rigid ducting in our system could go, where the distribution boxes would go and how much stuff I needed. They still insisted on sending materials I know that I will not be requiring. If you need any plastic 125mm ducting, you know where we are 🙂