Gone West

Think I'll have to disagree with you on that one.

I have a 110mm AAV on top of the main waste pipe in the centre of the pipe runs and a 50mm AAV at each end of the 50mm pipe runs which join each side of the main pipe. One for the bath end and one for the ensuite shower end. It's just a bit of redundancy in case there is a problem.

1. Should be higher than highest waste although some makes work below that level. 2. I have one 110mm AAV and two 50mm AAVs. 3. Can do, I've got mine at ends on pipe runs. 4. Doesn't need to go as high as loft. I have mine behind false walls in with concealed cisterns.

The problem is, the workmanship is poor, so that in reality the B rating for newbuilds is not really of that standard, and it is the poor workmanship that needs to be addressed.

Welcome to the forum. Have you tried pushing a screwdriver into the wood to see if it is rotten? Unless it's been soaked for some time it's probably just discolouring.

Interesting mix of units. Which do you prefer working in? Although well into OAP years I now struggle with feet and inches whereas my mate converts metric to imperial before doing anything.

If we move away from standard brick and block construction towards panelised houses built in factories it would be easier to remove poor workmanship.

We have a Genvex Combi 185LS compact unit which provides MVHR, warm air heating and DHW using an EASHP. IIRC it weighs 210kg before plumbed in and over 400kg when full. It requires a base suitable to support 500kg/m2, not really suitable for a loft installation. Nilan are another company offering similar products.

We used Sovereign SX70 white woodstain in the 90s internally and externally on all the windows and doors. It was very easy to use and it never peeled or cracked. It gave a nice satin finish. They may have changed the recipe since then of course.

There a lot of SAP assessors who can be accessed online and they will want copies of the plans and other information. It will probably cost IRO £150 based on what we paid. This is the first company that came up on a search list. https://www.buildenergy.co.uk/what-are-sap-calculations/

Can't you get an as designed SAP done which should give you an idea of the EPC?

We have appealed twice and had the band reduced in both cases. It's a simple process, which they may well challenge, as they did with our first appeal. It went right to the line with them dropping out of the tribunal process with only a week to go before the hearing.

I used Floplast and never had any problems will seals distorting etc. The important thing is that the pipe ends are chamfered and to use a smear of silicone grease on the pipe end before assembling.

There will be convection but some of the rising heat should be lost through the trickle vents in the windows upstairs so hopefully it won't be too hot. The problem is that trickle vents can be affected by the wind and it's difficult to know how effective they will be at any particular time. I wouldn't have thought that the ground floor will end up being cold though. It will probably mean tweaking the number of trickle vents that are open on both floors to obtain the best balance.

Yes there would be a degree of passive stack effect but how much would depend on the total area of the trickle vents. It would cause some probably noticeable draughts. We use passive stack ventilation in the summer to cool the house by opening the bathroom roof window. It can be very effective. Sorry re-read your post and the answer is no.

We've got a Dymo LetraTag and have ended up using it far more than we thought we would.

Worked for us. IIRC we sandwiched the existing panel with 6mm ply although I can't remember the grade exactly.

We had catflap in our old bungalow back door which we didn't want. I took the catflap out and fitted a piece if thin plywood on both sides, painted it and it was still fine when we demolished the bungalow fourteen years later.

It will be interesting to see how interested your BCO is in the ventilation calculations. Our BCO wasn't interested at all. We use the EASHP to heat our 180l DHW tank and as we never use that much hot water at a time the tank recovers quite quickly.

Yes I agree, that's why I said there was confusion because you were talking about @Thedreamer's build and I was talking more generally about the GS200 as was first discussed by the op. We got there in the end.

Correct. If an older house has an existing ventilation system ie trickle vents and I add one of these units then I haven't found anything in Part F that indicates I have to update the ventilation levels. I therefore don't need to extract 50l/s from inside the house but can extract a proportion of that from inside the house and the remainder from outside the house. I will just be enhancing the existing ventilation system.

No it wouldn't because I would only be drawing, in my example, 17.5l/s the remaining 32.5l/s would be coming from the external vent.

I understand what you're saying but from a practical point of view if I still lived in my old house with trickle vents I could fit one of these units and draw 35% of the air from inside the house and 65% from outside the house. I would not be replacing any existing ventilation just enhancing the ventilation that already exists. I think the confusion is that you are referring to a new ventilation system using one of these units and I am talking about enhancing an existing system which uses trickle vents in an older house.

I'm not explaining myself very well. Taking my house as an example. The bathroom needs ventilation at 7l/s, kitchen at 8.5l/s and shower at 3l/s giving a total of 18.5l/s to ventilate those rooms sufficiently. That leaves a requirement of 31.5l/s from the external vent to give the required flow for the heat pump. The four vents could be balanced to provide the correct flows. The rooms need ventilating at that rate and therefore heating whatever system is used. Most houses have trickle vents which would provide the required airflow into those rooms. It's not perfect by any means but for a lot of houses would be a good solution.

In our area in the summer when the sun shines, in the afternoon there is always a breeze. This helps to prevent a heat build up on the surface of the roof, therefore decrement delay is less of a factor. Unless your property is well sheltered I would be more concerned about heat loss. Presumably the room has good ventilation.