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AFAIK you can change a FIT system inverter to a hybrid with battery and that's within the FIT rules. If the battery is capable of charging from the grid then you have to change the FIT generation meter to a bi directional meter that can give a net reading of exported energy less anything imported. That then gives an accurate reading of what the PV has generated and the FIT payments are based on that reading. This is my understanding but it's not advice:) Our 5kw solis S5 does up to 5kw on its back up output without a separate gateway/change over switch which is enough to power the "whole house" less the high loads the OP mentions...cooker, ASHP, kitchen ring etc. The CU that the high loads are on has a manual changeover switch so we can connect it to the battery if we want but we have to manage all the loads so as not to trip the inverters 5kw limit!!

I used screwfix foil tape and it was terrible, very thin and not very sticky. Then i tried SuperFoil which I found in Selco, more expensive but very robust and sticky. You get what you pay for and would use superfoil again. It’s hard to estimate a quantity as I found I used more in certain areas.

That 32 degrees on the manifold is the clue for me. I would check the blending valve on the manifold first and nudge it up in small steps, as it sounds like it is mixing in too much return water before the loops. Also compare the flow and return temperatures on a loop and make sure the actuators are actually lifting, because a stuck pin will leave a loop cold even when the pump is running. Tiles will still only feel mildly warm at normal UFH temperatures, so give it a good few hours after any change before judging it.

If moving to a hybrid inverter doesn't that kill you FIT payments, would have thought you had to stay with the PV AC coupled. A hybrid effectively makes PV direct to battery. So would have thought an AC coupled battery system more appropriate. Are you one of those systems that get stupidly high deemed export rates? If so I would make sure you dot and cross everything before buying and installing I would investigate if your proposed invert will allow that, normally hybrid inverters allow a small UPS supply not whole house. You normally need a system with a gateway in addition to the inverters and these as far as I know only come with AC coupled battery suystems.

@Dillsue The plan is now Fogstar 32kWh with Solis S6 5kW Inverter. Shipping in February 2027. Any obvious flaws, your thoughts appreciated. We have an 80amp single phase supply which goes to an SPD. This is then split into two consumer units inside the plant room, one for the main house and the other supplies two outbound SWA's, the garage where the storage will be sited and the outbuildings where the original 3.74kW PV array is located. We have a Cat 6 data line between the plant room (house) and the garage. EPS / Backup Mode: I want the whole house to remain live during a power cut via an automatic changeover switch, but with heavy loads completely isolated (ASHP, kitchen oven/hob, sauna, and electric shower). The backup system should automatically run only the critical background loads (~200W continuous draw: fridge-freezer, LED lighting, wastewater treatment plant, and rainwater harvesting pumps). Plan to use the immersion heater in the UVC in manual mode. Micro-Grid AC Coupling: I want the existing 3.74kW Fronius PV array armoured cable (currently landing at Plant Room Consumer Unit 2) routed into the Solis GEN/Smart port in the garage. During a prolonged blackout, the Solis should form a micro-grid to wake the Fronius up so the solar panels can safely recharge the 32kWh battery bank, utilizing the Solis frequency-shifting protection. Would apply for a G100 0kW Zero-Export Scheme to keep things straightforward and fast-track the application with the DNO. We use nearly 80% of our generated PV.

CT1 dabs on their own are the weak point here. The board heats and cools every time the stove runs, so a few blobs end up taking all the movement and eventually let go. I'd refix it mechanically and use the adhesive as backup rather than the main fixing. Check the plaster behind first. If any of it has blown or sounds hollow when tapped, cut that back, because the fixings need to pull the board tight to something solid. Then I'd back butter the board with a heat resistant tile adhesive (Vitcas do one, or a decent flexible cementitious adhesive) using a notched trowel so you get near full contact rather than dabs. Drill through board and plaster into the masonry and fix with masonry screws or hammer in fixings with a washer head, roughly 300mm centres and 50mm in from the edges, countersinking slightly so the heads sit flush. I wouldn't use fire cement, it's brittle and meant for sealing joints, and gypsum based plasterboard adhesive isn't ideal that close to the stove either. On the air gap, if the wall is solid masonry it's non combustible anyway, so the board is really just protecting the plaster finish. Still worth checking the clearances in your stove manual. Finish with tiles in heat resistant adhesive and grout, or a skim, and leave a small gap at the corner and edges for movement.

my technique wash hang the foil on your belt. You cant cut it clean and then get it off the backing paper, you need to rip it. So id pull it out to length, fold it over on itself and then tear it. That leaves a rough/slightly exposed edge and you can simply peel the packing paper off. Its still a big job due to the square footage but i found it fairly satisfying.

There are a number of simple, freeware, bookkeeping programs available, why not use one of those. (I find using other people's spreadsheets quite time consuming and not intuitive)

I bought some of this the other week very similar to the stuff I bought 5 or so years ago. Nice and sticky and thick enough to be robust when installed. https://amzn.eu/d/04YOmIBN

Is the room up to temperature? And how how have you given it to heat up? UFH doesn't or shouldn't have a hot floor. 32 degs is below body temperature so it will only feel tempid.

SITUATION. Systems all checked: Pipes flushed, a sparky has checked electrics, new combi boiler (£7.5k ouch) and providing water to required temperature, thermostat calls for heat, a new actuator (replaced 1 week ago), mixing valve checked, pump checked (set at III or II), flow meters showing 1.5, temperature showing 32 degrees. PROBLEM. Water supply pipes up to manifolds hot but tepid once in manifold. Floor tiles not warming (chill taken off). I believe too much cold water being mixed. QUESTION. How do I increase temperature of water going under tiles?

I found that the stuff from SF was very poor. Not very sticky, very thin and fragile aluminium, but didn't come cleanly off the paper either. Perhaps they use varying sources then brand themselves. Otoh tyvek is super sticky.... and yet easier to use.. I got it at TP where they also had some unbranded... they assured me it was the same, and it did seem to be. The dearer stuff was better value. If you have any left you will use it elsewhere. Quantity? In the perfect world you use 3.6m per board on large areas. Being diy you should have minimal waste on boards, by using offcuts, but more tape. 5% waste on board, 15% on tape?

I used aluminium foil tape on my aluminium coated VCL and it stuck really well (cannot get it off easily well), have sections still exposed and 5 year later all good. However used exactly the same tape on PIR boards in the garage and it was very hit and miss if it actually stuck.. would say 90% was fine the other 10% I had to clean the contact areas.

Logically, if the boards are a bit dusty from trimming, or storage then adhesion can be an issue with foil tape, and if you try to use for bridging an angle, or gap it is easily punctured. I also used this Tyvek tape, bought a box of the stuff - brillant stuff, sticky and tough!

I put skamotec boards up around and over our's stuck and fixed to the wall with some vitcas adhesive, then a number of hammer in fixings per board. It was tiled over, rather than plastered though.

Is an air gap required?

We had exactly this problem on our build, so a few things we learned. JpManning’s columns are a good start. Two things we’d add: log quotes as well as invoices, so you can see what each stage is heading towards rather than just what you’ve spent, and keep contingency as its own line so it doesn’t quietly get spent on upgrades. One small thing on VAT that I think is right but best to check: for homes completed on or after 5 December 2023, the DIY housebuilder claim has to go in within 6 months of completion (it used to be 3). Worth checking on gov.uk before you rely on either. If it saves you starting from scratch, we made a free spreadsheet with budget, quotes, payments and VAT tabs: https://www.selfbuildbudget.com/downloads/self-build-budget-template.xlsx In the interests of being open: we also built a budgeting app for this on our own build (Self Build Budget), but the spreadsheet is free and works on its own. It's early days for the app and we're learning as we go through our project so happy to share a free access code with anyone that wants it.

That arrangement looks sensible to me for that spot between the taps, especially as it is not left under pressure when the taps are closed. I would just keep the flexis with a gentle bend and no kink, and leave them where you can see and reach them for a quick check. After you first run it, dry the joints and check again after a day, as a slow weep is much easier to catch early than after it has been boxed in.

Hi all I have a freestanding wood stove in a room corner. The walls are solid, plastered. Cement board was fitted to the two walls to prevent the plaster from cracking and has performed well, but it has come unstuck. The installer fixed it with dot and dab blobs of what I think was CT1. So I'm looking to refix them and wondered what's best? Cement board screws (or would other types of screws work, and if so what's best)? Some type of appropriate no nails type adhesive? Fire cement? Plasterboard adhesive? Or a combination of some of these? Would much appreciate any thoughts and advice. Many thanks

Right that's the floor finished Now to deal with the leaky soil pipe bosses that are imperial pipe and have knackered seals (which will be sooooo much fun with 4m of soil pipe above it)

I've used mountains of foil tape in the floor and ceilings and found it totally fine. Was left up on the ceiling for a year before I boarded and it was still stuck solid. As for estimating how much, I just bought a load of it and when I needed more just went and got it, no method in my madness. Just any old stuff from Screwfix worked for me, some has backing paper some doesn't. When you get in the zone and your technique down it just flies on.

Correct. As above, 20A max.

in most systems the plastic part is just a gutter really, the tiles are retained by a clamping plate that is screwed down. You could always look for an interlocking ridge system?

I've looked into this before and I'm pretty sure you can't put 16A commandos on a 32A radial without local protection. Normal UK mains wiring has fuses in the plug, commandos don't. Except in fault conditions (which fuses are supposed to be there to protect against).

The RCBO (MCB or whatever) is there to protect the fixed wiring, not whatever is plugged into it. The current is drawn by whatever is plugged into the 16A Commando, and therefore should only ever be 16A or less (continuously).