marshian

Well Floor replaced and over boarded with 3.6mm ply as planned - nice and flat and very very solid. now ready for tiles unless I need to coat the ply with something to stop it stealing the water out of the adhesive too quickly?

I got some samples from Millboard - it's much thicker than normal wooden decking but the samples looked really good - we put wooden decking down in 2007 and it's reaching end of life (it's treated every year in spring and autumn) as there are sections where the edges have rotted and I had to replace the odd section - the structure under it is solid and well ventilated so next years project is replacement. I need to understand how the fixings work because I don't want to re-do the structure to suit fixed fixings

Just how bad is your eyesight?

Space heating is the biggest driver for gas usage - in my case 80% of my annual 10,000 kWh of gas, HW generation comes second at 19% and "Cooking" is just 1% When I was researching ASHP v Replacing the existing boiler it was important to me to retain the gas for cooking as "we" like cooking with gas my understanding at the time was that this was acceptable (unlike a gas heater in a room which would have to be removed)

Not sure you are correct there. Whilst it would be expensive from a usage and standing charge perspective to retain mains gas connection to a house for just cooking in a house that had converted to ASHP it is permitted under the rules

I'm not counting the screws............................... (It's a lot!!!)

I remember when my Viessmann Gas Boiler was being installed and the "heating engineer" explained the weather compensation curve - he didn't understand it at all and got very flustered when I explained it to him as clearly a customer shouldn't have more understanding than a heating engineer..... But I should have realised when I got an S Plan set up and not DHWP (X-Plan) which I'd asked for (He did rectify that once I pointed out what he'd agreed to) It's quite sad...........

Possibly - not sure on what advantage that would give me?

What is that or should I google?

interesting point thanks for that - current tiles have been down since 1994 - never re-grouted in that time and none was missing till I started lifting sections - floor joists are less than 400 mm centres with 18mm T&G chipboard. I'm a bit hesitant to increase over-boarding thickness because it will create a step at the threshold between rooms and adjoining hallway

Background Back in 1991 when we moved in the utility room, kitchen and conservatory had hard vinyl tiles on the floors - they were stuck down with some bitumen type adhesive - took me a good week to get them all up (they chipped and cracked and only came up in little bits) and then getting what was left of the floor involved some fairly aggressive solvents. Mrs Alien wanted ceramic tiles for all of them (so I bought enough grey square ceramic floor tiles to do all of them) so after making good the floor I over boarded with 3.5 mm ply nailed to the chipboard and then tile adhesive and tiles. My reason for the over-boarding was if she ever wanted to change the tiles I could lift both tile and ply up in sections and not have to scrape/chip/grind tile adhesive off the chipboard. Now my one big error was not doing wall to wall tiling in both rooms - I did in the conservatory but I did that one first (Hindsight is wonderful) and I only did the floor area in the kitchen up to the kick board and the same in the utility. The downside is it creates a weir if you have any water leaks under the cupboards and you don't notice the leak until it's been happening for a while. (water softener I'm looking at you now) So right now I'm embarking on re-doing the utility (kitchen is next as I'm transferring some of the wall and floor units to the utility before the new kitchen arrives in Nov/Dec) it's a 2m x 2m room that is now empty and I'm replacing most of the floor because it wasn't great last time I tiled it (think floor areas under units that looked like dried out wheatabix) I spent Saturday lifting the tiles and over-boarding - once I'd got a start point a decent pry bar, claw hammer and bolster meant it lifted fairly easily in small sections. I could then take outside and with tile face down fold the ply to break it on the grout lines and I ended up with a half full wheelie bin So the current plan is new chipboard floor - 3.5mm ply over-boarding (stapled) and then wall to wall tiled and grouted before units are moved in. Am I missing an alternative method - neither kitchen or Utility are a wet room but both have wet services!!

My understanding is the BUS Grant doesn't mean you have to give up gas cooking - when I looked into ASHP rather than replace the gas boiler (Mains Gas) we would be able to keep the gas hob (albeit with the standing charge cost issue for a very small amount of annual gas usage) So unless things have changed you should be able to keep your LPG gas cylinders but I think 4 would probably be over kill for the usage so drop down to two as @ProDave suggests

Rightly or wrongly before tiling I've always over-boarded chipboard floors with 5 or 6mm ply and then stapled it down (rather than glue or screw) then tiled over the top of the ply. My logic was if I ever need to replace the tiles it was easier to get the tiles off then the 5 or 6mm ply up with the adhesive to get back to a nice clean and level surface - re-board and again and re-tile. I get to test my plan shortly as both Utility and Kitchen floors need re-tiling!!! The Kitchen floor needs replacing fully replacing due to a water leak that got under the floor tiles 😞

Early 1980's build 4 Bed Detached with 113 m2 of floor area across 2 floors (Garage not included) Background in a thread below

I don't think it does - maths is just maths Whenwe bought the house it was 23,000 kWh of gas annually - I got it down to 16,500 kWh of gas a year for CH and HW with typical home improvements before I started my optimisation efforts - I reduced it to 8,500 a year (with scheduled heating) but it's now stable at 10,250 running 24/7 with a DHWP and WC set up (I'm running a gas boiler like a heat pump) Latest change should see me back below 10,000 within a year