-crashd

You're right, I meant loft conversion, not extension. Apologies!

We're coming to the end of a loft conversion in a bungalow (thankfully!) and looking at our plans for an extension. The staircase is "in" but new stud walls not yet made or plasterboarded. There's a gap between the existing ceiling (which is of lathe and plaster construction) and the floor of the extension (which is suspended insulation under TNG etc..). I wanted wanted to ensure this gap is well insulated internally (so where it meets the staircase) as well as externally (which I assume will be stud / block work / guttering etc...). I wondered if anyone had any advice that I could put to my builder to ensure this is the case, obviously they're going to have an opinion too

Really useful, we've already engaged and got quotes from a few specialists, our general contractor isn't doing the EWI. We've gone with one who has lots of residential but also does commercial, and specialises in EWI. Seems legitimate (although who can even tell).

Thanks Simon - they seem pretty reasonable other than this suggestion but I take your point With the EPS beads, does that not compromise the airflow in the void?

Currently run down the side of the house and in through the back, then underfloor. We're taking it all out and replacing with new though so it's in our gift.

Thanks @Ferdinand - I'm an absolute newbie to this stuff so it's good to hear that my thinking is along the right lines. I'll pick through the Boffins thread and see if I make hide nor hair, and I'll be having a good chat with the builder next week

It's a timber board / joists / void construction. I did think about screed but cost + lack of ventilation worries me a bit ...

That's right - their suggestion is to not insulate underfloor and replace the existing floorboards with a TNG chipboard of some kind.

As per a previous thread We're in the throes of adding a loft conversion and a rear extension to this property. We're also renovating/modernising bits as we go. We're thinking about what to do regarding the existing ground floor flooring situation. Our plan is to lift the cheap click flooring + underlay, pull the floorboards up (some of which will definitely need replacing as there's a certain damp smell in the kitchen/bathroom) and insulate underneath then lay overboard UFH and new flooring on top. Our builder suggested that if we take up floorboards completely and instead lay down floor grade TNG board, underlay, overboard UFH (the Wunda board system) and then new flooring, and it's all done correctly, we'd save money on labour + materials and wouldn't notice the difference. I feel like this is probably an ok solution but seems like the 'easy out' from our builder - what do you all think? We'll also be putting in EWI, new boiler, double glazing etc... for reference. D

@JohnMoThanks for the thoughts - there's an unvented Vaillant ecoTEC Plus 415 (https://www.vaillant.co.uk/for-installers/products/ecotec-plus-412-415-418-424-430-and-435-3328.html) and a hot water tank. I don't really know enough about heating and hot water options to know if we'd need to replace the boiler for this setup initially?

Hi all, As per my post here : we're currently in the process of planning an extension/loft conversion/part-reno of a bungalow in Twickenham. We're keen to look at a heat pump as our heating solution but aware of some of the requirements (around insulation etc..) and some of the potential downfalls, including initial outlay. The house currently has a relatively new gas combi boiler. One of my thoughts is to do the initial work to prepare for a heat pump - wet underfloor on the ground floor and appropriate piping and radiators on the upstairs - but retain the gas boiler setup for now to alleviate some of the financial investment, and in the hope that pump costs and efficiency may improve. Is this a stupid idea, and if not, what else should we consider?

Really useful advice, thanks @Marvin

The wonders of Rightmove That one is really nice, but our family / work situation means we'll likely need an office/spare room (hence the loft conversion idea). It's within budget, but we definitely wouldn't have the 70k+ for a loft. And they don't appear to have EWI, so perhaps there's IWI?

Thanks @Marvin for your time, that's a really thorough answer : ) We're definitely looking to insulate the floor, the existing exterior and replace all the existing windows. If this work is done to a high enough standard, and the new work is also up to the more modern high standards, is there any other areas we need to be concerned about relating to the A and I of your AIM metric?

@Russell griffiths we're keen to reduce carbon usage, we can apply for a £5k grant come April and are planning to stay in this house for the long-term and I can only assume gas prices are going to rise. Obviously if everyone tells us to stay away from ASHP given the existing fabric then we may reconsider. Are we on a hiding to nothing trying to refurb the house though? That's one of the things keeping me awake at night at the moment!