flanagaj

I am keen to hear about the GSE as like you say, it negates slate or standing seam for a large area. Haven't found any online resources that are detailed enough to understand how you install GSE with standing seam.

That is correct. The solar PV quote was just to see how much it would cost and I cannot afford it.

I take your point. I am really interested in fitting standard PV panels using the GSE tray system. It makes complete sense to effectively use the panels as a roof covering as opposed to fitting a roof underneath.

I don't follow why it will cost you more. If they zero rate the VAT, haven't you just not paid VAT on the purchase?

So we have had a quote for both aluminium and aluminium timber cladding. The aluminium quote for supply only is surprisingly 2.5k more, but when I then apply the 10% August discount (not sure it's a real discount) and the installation cost which is 3.5k cheaper, the aluminium offering is 5k less. I was always told aluminium clad is more expensive as it's a better product and the U values are lower, so now I'm sceptical about the aluminium quote and wondering whether I could reduce the installation cost of the aluminium timber cladding by installing the smaller 1.1m*1.2m ones myself. The ali-clad installation cost for 60m2 is nearly 27% of the cost of the doors and windows!

These are the bonded panels and not sure who is creaming off the 9.5k

I have just discovered the GSE panel option, but there is very little information regarding using them with standing seam roofing sheets. Keen to hear if anyone has an update or a resource which shows how this can be achieved. I suspect that by using conventional solar PV panels and GSE, you can save a small fortune over solar PV bonded to standing seam sheets.

This is a potentially interesting option. I had a quote back today for having PV bonded onto the seam sealed roofing sheets prior to installation and for 8.5Kw it is £10.5k. I am keen to understand what you are paying for your PV and how much the materials are to mount the PV cells. I am planning on fitting the seam sealed roof myself and that is coming in at ~ £50/m2 supply only. Do you have a link to the PV supplier you are using?

I did look for it, but could not find it. Will that be cheaper than going the grant route?

But does it work out cheaper than buying the ashp and cylinder outside of the grant scheme and then getting a mcs certified installer to commission it. As a cynic, I can't help but think the grant scheme is just a licence for installers to just make extra money.

"MCS Umbrella scheme" - thanks, I'll look into that.

I know this might sound like a stupid question, but how do you go about getting the grant for a heat pump and making sure that is was given and not swallowed up by the supplier. My plan is to purchase a 5K ASHP that can run in both heating and cooling mode and I also want a 250 litre cylinder, but I have no idea whether the price I see listed on websites for the ASHP is with the grant taken into consideration or not. Is it possible to get all the parts as supply only and I can then fit them and get them commissioned when ready?

So Jeremy's heat loss calculator gave me a 3.7Kw value. I plugged these details into ChatGPT and it has come up with the below. Anyone care to cast their eye over it and see if what it is suggesting looks correct. Awesome—thanks for the room schedule. Here’s a crisp sizing plan that fits your 5 kW reversible ASHP, gives proper bedroom cooling with dehumidification, and uses UFH for gentle background cooling downstairs. Bedroom cooling (use small hydronic fan coils) Rule-of-thumb sensible loads in a well-insulated UK home: Standard beds: ~35–45 W/m² Master: ~40–50 W/m² (bigger volume/glazing) Recommended FCU sensible capacities (at ~7/12 °C water, 27 °C room): Room Area Est. sensible load Suggested FCU Master 30 m² 1.2–1.5 kW ~1.5 kW unit (quiet on low) Bed 1 19 m² 0.7–0.9 kW ~1.0–1.2 kW unit Bed 2 15 m² 0.6–0.8 kW ~0.8–1.0 kW unit Bed 3 14 m² 0.5–0.7 kW ~0.8–1.0 kW unit Notes Bedrooms are carpeted (good for heating comfort; irrelevant for FCU cooling). These small FCUs give you latent removal (dehumidification)—the key to comfortable sleep. Downstairs cooling (UFH + optional 1 FCU) Polished concrete is perfect for UFH cooling, but radiant floors don’t dehumidify and must stay above dew-point. UFH cooling outputs you can bank on (safe, quiet): With supply ≥18–19 °C and typical UK indoor ~24 °C / 50–55% RH → ~20–35 W/m² Expected background cooling from UFH: Kitchen-diner 35 m² → ~0.7–1.1 kW Lounge 19.5 m² → ~0.4–0.7 kW Downstairs UFH total: ~1.1–1.8 kW Optional add-on for muggy days / solar gain: 1 discreet FCU in the kitchen-diner, ~1.5–2.0 kW sensible, to mop up humidity and peaks. (Highly recommended with big south glazing.) Diversity vs your ~5 kW ASHP Likely coincident demand: Master + one small bedroom + some UFH ≈ 3–4 kW, which your 5 kW unit handles easily. Even with all bedrooms calling, fan speeds modulate and loads are rarely simultaneous at peak. The optional downstairs FCU can be limited by control if needed. Control & safeguards (important) FCU loop: chilled water 7–12 °C, each FCU on a 2-port valve, own small circulator, proper condensate drains. UFH cooling loop: enforce dew-point control. Example: at 24 °C / 55% RH, dew point ≈ 15 °C → cap UFH supply at ≥17–19 °C (controller with RH/temperature input or dedicated dew-point sensor). Modes: Heating: weather-comp 35–40 °C to UFH. Cooling: FCUs on 7–12 °C; UFH at dew-point-safe setpoint. DHW: priority reheat; weekly 60 °C pasteurisation. DHW (2 occupants, occasional 6) Cylinder: 200–250 L, heat-pump coil ≥2 m². Recovery: 5 kW ASHP reheats 200–250 L (10→45 °C) in ~60–90 min. On guest days, schedule a mid-evening top-up. Quick bill of materials (to brief installer) Reversible ~5 kW air-to-water ASHP, min modulation ≤1–1.5 kW. HP-ready 200–250 L cylinder, ≥2 m² coil, DHW priority + weekly pasteurisation. Bedroom FCUs: ~1.5 kW (Master), ~1.0–1.2 kW (Bed1), ~0.8–1.0 kW (Bed2), ~0.8–1.0 kW (Bed3). Downstairs: UFH cooling with dew-point protection (+ optional 1.5–2.0 kW FCU in kitchen-diner). Hydraulics: FCU chilled loop with own pump; UFH on mixing/limit control; 3-port diverter for DHW. Low-loss header only if flow stability demands it. If you want, I can translate this into specific FCU model sizes (wall/console or slim ducted) and a control sequence (setpoints, interlocks, sensors) tailored to your preferred brands.

After some deliberation, I think I am going to ask the architect to submit a variation of condition for solar PV in the south facing roof. We have a 17m * 4m roof which is going to be standing seam. I did consider Catnic Solar, but I think the cost will be way too much and I was wondering whether there are any other options to have solar integrated into the roof. I am not a fan of the panels being fitted on top of the roof as I think it looks clunky. Has anyone installed solar PV with standing seam and if so, what did you go with. Pictures would be great.

I have started doing my own research, but unsure whether it is correct or not.

I have become rather bewildered regarding what aspects I need to do and it what order. The technical architect is currently doing the drawings for building regs submission and another company (UK building compliance) are doing the following. L1A SAP 10 Calculations New Build (inc Design, As Built & EPC)Design Stage SAP L1A Assessments and PEAs a. Assessment under the 2021 Part L Building Regulations; b. Design Final Checklists for Building Control; c. Predicted Energy Assessments (PEAs); d. Thermal Bridging Calculation (y-value) based on Accredited Details (if used); e. Thermal Mass Parameter Calculation; f. Assistance with thermal, heating, lighting and renewable specification (including revisions); g. To include for unlimited specification revisions; h. Access to Dashpivot app for recording of photographic evidence. As-Built SAP L1a Assessments and EPCs a. Assessment under the 2021 Part L Building Regulations; b. As-Built Final L1a Checklists for Building Control; c. BREL report; d. Verification of photographic evidence; e. Energy Performance Certificates (EPCs).1.00310.00310.00 Water Efficiency CalculationsPart G Water Efficiency Calculation/s, consumption to meet requirement of 125L (or less if required) per person per day. Includes PDF Report.1.0095.0095.00CIBSE TM59 Overheating AssessmentDetailed overheating assessment in accordance with CIBSE TM59. To demonstrate compliance with Part O Building Regulations 2021. To include for an appropriate sample requirement & x 1 re-run of the calculations Do I need to wait for the details of this information, before I can start designing the UFH and ASHP? I did put the details in Jeremy's spreadsheet, but I am bemused as to what order to do things. Any pointers welcomed.

I'll mention this. Thanks

Sorry, but that made me 😂

I'm not disputing, but can you explain your reasoning? My only reservation (I am a Luddite), is that a cavity is meant to breath and a cavity that is fully filled cannot?

I am glad that the point regarding batts vs PIR insulation has been raised. I have just calculated that I need 252m2 of insulation. If I cost this up for 90mm T&G PIR, it's an eye watering ? 5.7k (£22.50 / m2) which is about 3k more than cavity batts. The architect has done the drawings with a 150mm cavity which will means that we could in theory go 140mm cavity batts? Our property is not sitting high on a hill and is not very exposed to the elements. The top part of the house is also timber clad. Unless there is any real benefit to having PIR, I am considering changing to 140mm with a 10mm gap, or would people just suggest go full fill?

Given the cost of adding a UFH loop into the slab is going to minimal in the grand scheme of things, I think that is what I am going to do. Will be a perfect man cave for tinkering away during the dark and dreary 5 months of the year.

That's a fair point.

Sorry. TA (technical architect)

One of the requirements for our build is that I want a garage that is not cold and damp. As a result the TA has specified cavity walls as per the main house, 150mm celotex floor insulation and 150mm Kingspan TR27 roof insulation. This obviously comes at a cost and I am wondering whether it is overkill and I could reduce the floor insulation and also the roof insulation a bit. There is no door connecting the garage to the house. The garage will be my workshop and gym so having something that is not Baltic during the winter months is the main criteria. I am also thinking of putting a radiator in too.

Thanks all. I am planning on working with a local steel fabricator for the steel aspects and will manufacture the treads myself. Fortunately, I can manufacture the treads as I baulk at the £200 / tread that people on eBay are charging. One option would be to have steel rods for the balustrade, which are threaded and connect each end of the treads to a steel beam in the ceiling.