Gone West

Many thanks, hempcrete is something I shall be looking into. I have seen it used on buildings featured on TV programmes but I had forgotten about it, old age 😟.

I think it is also linked to age and fitness/health.

Many thanks to all the contributors. This is what makes this forum so useful, a lot of varied information from knowledgeable people. I have decided not to insulate the wall and risk any deterioration. There is no sign of damp or mould, even near the bottom of the wall, so I shall keep it as it has been for the last fifty years even though I shall lose the advantage of having insulation.

I'll think about that. It needs to be big enough that the surrounding area doesn't have an effect.

We get a lot of driving rain but we don't get many freezing nights here. The render is well painted and is at least fifty years old. I am reluctant to alter anything that has worked for fifty years, so covering the inside of the old walls with insulation requires a lot of thought.

I would be very suprised if the old parts of the house have a DPC. The whole house, original 1840s and 'modern' 1970s is cement rendered and there is no visible damp on the inside walls. That's why I was carefully considering whether to cover the inside of the old walls with insulation, in case that takes heat away which is helping to keep the walls dry and therefore the room comfortable.

Presumably a waterproof additive would solve the problem.

So a cement rendered stone wall will keep rain out, as long as it's not got cracks.

The house had been empty for a year before we bought it, and the climate is quite humid down here. My theory was that the fabric of the building, which is a mixture of sandstone and dense concrete block, hard plastered, had absorbed moisture. After we moved in it took a long time for the house to feel comfortable and at the time @SteamyTea explained about the large amount of energy required to dry out an old structure. I am confident that that explanation is correct and now the house is warm and comfortable. It's all covered in layers of old plaster. The house has had a chequered history. Started, around 1840, as a pair of farm workers cottages, stone walls on ground floor and cob upper walls. In the 1970s it was knocked into one and the cob walls removed. Unsound stone walls were replaced with concrete block walls and new roof trusses and concrete tiles added.

No. Now the air temperature has been 23C for a long time the wall surfaces feel warm. We had an old wet door mat out in the unheated boot room and that did smell damp until I dumped it.

Many years ago I had a problem with water running off the road onto my drive. I spoke to Highways about it and they put a 40mm high mound of tarmac along the length of the drive. They said 40mm was the highest they could safely put it.

Thanks, that's really interesting. Food for thought.

Yes, it's the "may/should" bit, I'm not sure about. If the thermal mass is hidden, am I going to end up with an old wall that becomes cold again.

Yes I agree, but what will be more comfortable. We found when we first moved in that it took the best part of a year for the temperature of the fabric of the building to stabilise. @SteamyTea patiently explained about how much energy is required to dry out the old walls. The house felt cold even though the thermometer was reading the right temperature. I'm not sure that covering up the solid wall with a small amount of insulation will help and might make it less comfortable.

Everybody knows what it means though. https://www.greenspec.co.uk/building-design/thermal-mass/ https://www.designingbuildings.co.uk/wiki/Thermal_mass_in_buildings

I have an external wall in the kitchen which is around 650mm thick and is of sandstone/rubble construction. I am trying to work out if adding a thin layer of insulated plasterboard, say 25mm PIR, will improve comfort levels. Alternatively if I just plaster skim the wall, will the comfort level be better because of the thermal mass effect.

IIRC our house was only 120m2 for PHPP. I think unless the fabric of the building is significantly better than PH maximum levels, ie overall values U=0.1, the combi 185LS would struggle to keep the house warm. That is unless the interior is around 20C, but we did keep ours at 23C. That Plumbavent site is a good find, I'd have rather dealt with a UK company than Danish.

I fitted a Genvex Combi 185LS back in 2017 and IIRC paid around £5000 buying it direct from Denmark. At the time it was around £8000 from Total Home Environment. The reason for buying it was that it's a compact unit offering MVHR, DHW and warm air heating and it worked well in our PH. The only downside was it had an enamelled steel DHW tank with an anode.

No best time, but I've found it easier in the summer after a long dry spell, when a lot of it falls off of it's own accord, and the rest can be brushed off.

The EASHP in the Genvex 185LS I had, was rated at 585W. I don't know how it worked to heat the water, as it just switched between heating the water in the tank to heating the air in the MVHR ducts. Ground Sun produced a small ASHP a while back called GS200.

I used one of the test kits from Amazon around six years ago. Everything needed was included in the kit and the results were back in a few days. Mine came back as positive Chrysotile.

I've recently fitted some slotted concrete fence posts, I cut a couple and they had four lengths of rebar, one near each corner.

I designed and built my PH in East Kent, with walls, roof and floor 0.1 W/m2K, triple glazing and airtightness 0.47ACH. We heated the whole house to 23C with just electric towel rails in the three bathrooms, supplimented with warm air from the MVHR with built in EASHP. It would have been massive overkill to have installed any sort of conventional CH. I think a wood burning stove would produce too much localised heat in that sort of house.

Yeah we managed to transfer it and we get just over £2k a year in total 😀. There were no details other than the installation invoice when we moved in. There is an SMA Sunny Beam display but the total output bears no relation to the generation meter which has gone round the clock at least once or been replaced. The Sunny Beam is reading 45,420.6kWh currently and the generation meter is reading 3486.7kWh and when we moved in, it read 92845.2kWh, so there is a mismatch somewhere. I was hoping there might be a record kept by OFGEM, or someone, of historical annual output for every producer so I could look back over the last twelve years to compare yearly outputs.

I've bought a house which has a 4kW PV array installed in 2012 under the MCS. Is there a way of finding out the annual production going back to 2012?