Tony K

No I don't think I'm at risk of overinsulating. The columns are in the cavity (mostly). When filling from both ends did you use spray insulation, do you think you filled the whole column, and do you reckon you could've filled the whole thing from just one point of access?

Evening all. I have a steel goalpost frame with 2.5m SHS columns at either end. The columns sit in the blockwork cavity, and I would like to fill them with spray insulation. I can only access the top part of the columns now. Will I be able to fill an entire SHS column from just one drilled hole at the top end, or will the spray insulation fill an area near the hole too quickly for that? Cheers

Afternoon. I have received a range of quotes for an MHVR kit for my SB, which is a 100m2, flat roofed bungalow. The roof is made using posi joists, through which the MHVR system can be fitted. The quotes (for design and supply only) range from under 2k up to over 6k. Both the highest and lowest quotes stress the importance of avoiding a noisy system, and claim to offer it. Has anyone had any issues with noise from the MHVR system? Any advice on avoiding noise, and/or what to look for when choosing a system? Thanks

Those with passing interest in my tale of woe may be heartened to learn that I seem to have convinced UKPN of the error of their ways. When I first registered for a connection I used a web-form, which in turn generated a PDF of all the information I had supplied. This was emailed to me automatically, along with some standard gumpf. This PDF proved that I had informed UKPN from the outset of my desire to have a 12kw ASHP, and that their subsequent quotes of circa £3k had been on that basis therefore. UKPN had variously stated that... I hadn't originally told them about the ASHP (incorrect, see above). They couldn't honour the original quote as it was over a year old (true, but they provided me with a refreshed and almost identical one in October 21). My offer to drop from three phase to single didn't help to 'balance the network' (they have now agreed to the connection on the strict proviso that I only have single phase - the triple phase was not my idea anyway, it was suggested to me as a future-proofing measure by... you've guessed it, the UKPN surveyor). All I have to do now is wait until next week when the UKPN surveyor comes out to have a look at the site. For the third time. If you are having trouble with your DO, I hope this helps.

Cheers @ProDave, I have made the house as efficient as I can. It's not passive of course, but does have good insulation, has UFH, has enough glazing to allow the slab to soak up heat etc. As per your advice I may well go for an external oil boiler ahead of an eventual switch to ASHP, but does this not have implications for the type of UFH I use?

My own experience has been thus: 1. Check in advance that the electric network is within reasonable distance of your SB. 2. Tell UK Power Networks that you want to build a new house and heat it using a 12kw ASHP. 3. Get a quote from UK Power Networks for an electric connection for your SB. They will come out and take photos and do you a little drawing and everything. In my case the cables are about seven metres away from the new SB, under an unmade track. Connection fee quoted at circa £3k. 4. Spend a life-altering sum on the SB, up to and including the roof. 5. Tell UKPN you want to proceed with connection. 6. UKPN tell you that the network isn't up to the job, and that it'll cost you £60k instead as they need to do so many local upgrades to facilitate your ASHP. 7. Install a gas or oil boiler. Probably. It's terribly clever stuff. On your second point, be aware that whilst the planners can approve the presence of the PVs, that's just to do with the visual implications. They have nothing whatsoever to do with you being allowed to connect to the grid or not. Not that I am aware of any reason why the DO should object to PVs. Mind you, you can see from the above that I am on a steep learning curve here so don't take my word for it!

I have looked at the idea of adding an ASHP later on without telling the DO, but I believe they must be notified. I am in the middle of trying to engage the DO regarding possible spec amendments for the ASHP to alleviate their concerns, but they aren't showing any obvious inclination to have that conversation, hence me trying to explore the fall back options. Thing is, the more I find out about it the less it seems that there is a reasonably future-proofed alternative to the ASHP.

This is the concern of course. Perhaps another way to look at the gamble is: If I get a gas boiler now, will it be easier for me to connect to the electric grid with an ASHP in 12 years time than it is today? I presume most electricity DO's will have had to improve network capacity in anticipation of mass-ASHP use?

Afternoon. I am in 'discussions' with my DO about being allowed to connect an ASHP to the network. If they refuse then I will need to look at alternatives. I have discounted biomass due to the size required for the boiler and storage (it is a small SB with a very tiny utility room), so the obvious alternative to an ASHP is gas. Plainly gas is yesterdays product and it feels wrong to instal it in my SB. However, I am mindful of the talk that the gas network will be replaced by hydrogen at some point in the future. Have I correctly understood the nature of my gamble to be as follows: Will a new gas combi boiler last long enough to see us through until hydrogen becomes available?

Thanks @PeterW I had considered the safety implications of messing with such a powerful tool, but am not certain that I'd be able to screw into the steel effectively. Is that a straightforward undertaking, or does it require a specialist bit of kit?

@Thorfun Brilliant, thanks. Is there a particular fixing you found effective?

Hi, Has anyone ever used shotfired fixings to attach timber packers and framing anchors to a 203 x 203mm universal I-beam? The fixings would need to go through the horizontal top and bottom flanges, which are about 11mm thick. If anyone can suggest a suitable tool for the job I'd be grateful! Cheers

Afternoon all. To reduce impact, my SB is set into slightly excavated ground in relation to neighbouring land. This required some slightly fiddly waterproof tanking inside the cavity wall, which I undertook myself. The work is to the satisfaction of the building control inspector, and the warranty providers inspector hasn't questioned it. The SB is a single storey flat roof building with a very simple roof design. I am not a roofer, but am considering building the structure and doing the finish with rubber myself, albeit with some help from a former roofer on the detailed bits. The terms of my warranty include a standard endorsement that any works to waterproof the house must be backed by a ten year guarantee. If not, the warranty doesn't cover any damage caused by water ingress. I'm fairly comfortable that I did a decent job of the tanking. The cost of getting a guarantee-backed roofer to do the roof finishing seems unnesecary given the simplicity of the job and the fact I have access to a good former roofer anyway, albeit one without the backing of a guarantee. Does anyone know whether: 1. Any standard home insurance I take out after completion (including Building Control sign off) would cover the waterproofing? 2. The is any feasibility in taking out a seperate insurance policy to cover the gap in the warranty regarding water ingress? Which firms might supply this, and at what likely cost? Thanks

Thanks @joth I have pushed back on UKPN, and I do have a consistent point of contact there. I've argued that they have to stand by the quote they gave me for connection originally, having demonstrated that they were made fully aware of my intention to have an ASHP. I've also asked them to look at whether a different design would work. I'll investigate the implications of wet UFH rather than electrical. Specifically, comparative costs and effect on screed depth, but you make a strong case regarding adaptability. Thanks also @Susie I've never heard of either option you list, but will look into both now.

Thanks all. I am of course pressing my case for UKPN to hook me up to the grid. They knew I had an ASHP from the outset. In the event that I cannot get an ASHP, and given that GSHP is not an option on my site. what is the general view on the next best options? I was originally drawn to an ASHP because it protected me from rising energy bills. I appreciate that I may be asking how long a piece of string is here.

Thanks @J1mbo, but is the opposite true? i.e, could I install electric UFH and run it from a gas boiler? I presume certainly not, but I lack expertise!

Yes, I appreciate that. I had of course planned to use electric UFH, but if I end up having to opt for a gas connection then I presume I will have ot use water UFH. That's possibly fine, but isn;t as future-proofed as I hoped an electric UFH system powered by an ASHP would be.

@ProDave, Interestingly, I've just found a copy of the webform details I supplied to UKPN - I did tell them I would be using an ASHP and said it was rated at 12KW, but I replied 'Unknown' when asked about how often it would be started in one hour, the starting method and starting current. Is it as simple as me offering a soft start?

I wondered about that. Am I not obliged to tell them when I fit an ASHP though?

I don't believe they asked for one at that stage. The problem is these details are provided on webforms so I'd have to do some digging to find out if I was even asked the question at the initial stages.

@J1mbo and @ProDave, thanks for replying. I told UKPN the following, though I was quoting from various places and addressing a subject I have very little knowledge of: 'Regarding the required KvA, my electrician informs me that 23KVA will be appropriate, delivering a 100A fuse. In terms of a breakdown: No landlord supplies. No street lighting. No Lifts, Motors, Welders, Cranes or Silos. No electric vehicle charging point now or in the future (the property is not on the highway and has no off-street parking space). The property will have an Air Source Heat Pump: https://www.nibe.eu/en-gb/products/heat-pumps/air-source-heat-pumps/NIBE-F2040-_-228 Max operating current 23A which at 230V is 5.29kW. Starting current is given as 5A'

Happy New Year all. I planned to heat my new bungalow (100m2, flat roof, UFH, reasonable-to-good airtightness but not Passive) with an ASHP. My electric infrastructure overlords, UK Power Networks, came out twice to see me and gave me quotes to connect to the network for circa 3k. As the project has progressed UKPN now say they need £40k+ to connect me, as the local network won't support an ASHP. Leaving aside the sharpness of this practice for a moment, I am looking at alternative heating methods. 1. Am I right to think I can power the UFH straight from the electric grid? If so, does anyone have an idea of the costs of this heating strategy vs the payback period for an ASHP over its lifetime? I wonder if I will actually be worse off without the ASHP in the end? 2. I had not planned to have gas, but could do so if I had to. I presume I would then be looking at a boiler and water tank as per usual, but is there in fact a specific set up required for UFH and gas? 3. I couldn't find a way to make solar power work for me when I did my initial research. Partly this was to do with orientation of the plot, but more it was a question of upfront costs vs payback time, affected of course by the end of the grant system. However, a relative of mine now works replacing solar systems and can apparently get me quite a lot of good second hand kit for free, so I may review this option. Is there a good place to go for a reliable solar / heating design? Thanks

The sand looks similar to mine but the rest of your recipe is different. I'll have another look at the sample section just before I need to make the final decision. Expensive stuff that snowcrete, by the way.

Did you use snowcrete and building sand at 1:4 to get the result in your photo @Buzz?

Here it is. 4 building sand to one snowcrete. Not very reminiscent of snow.