Gone West

@lizzie I'm so glad you've got it sorted and are now comfortable in the house. Hope you are as successful with the UFH.

Welcome to the forum and good luck with future projects.

Are there alternatives in your area to having an Openreach line. I got totally pissed off with Openreach after months and months of arguing and them not doing what I wanted so I used a WiMax company. They installed everything within a few days, faster broadband and a landline number using VoIP and cheaper than BT.

Welcome to the forum Simon. Plenty of ICF self builders on here to quiz. Good luck with the project.

There are different types of spray foam. I can only really comment on Icynene which although we had to do a lot of trimming, worked well for us. It is sprayed on very thinly and expands IIRC about 100 times so layers of around 100mm are built up. It sets into a rubbery flexible foam that off-gases quickly and after a couple of days there was no smell. The only disadvantage I have heard about is that it doesn't stick very well to a cold surface so it's not a job for a cold winter. Icynene BBA.pdf Icynene Spec.pdf

If you attach a wide strip of membrane to the I-beams behind the ledger plate before fitting the ledger plate you can tape the membrane to that strip on the first floor and on the ground floor.

Our first floor metal web joists hang from a ledger plate that is attached to the I-beam wall studs. We used 300mm I-beams and extended them to 350mm by adding battens to the inner flanges of the i-beams. The ledger plate is the same thickness as the battens and sits on those battens and is nailed to the I-beam flanges. We don't have any membranes or tapes in our construction as the wall itself with the Icynene insulation is the airtightness layer. We achieved an airtightness result of 0.47ACH.

We paid £200 for a morning with no VAT.

They are exactly the same model by Scheppach .

It's an awful lot cheaper than Screwfix are selling it for.

That looks like Western Red Cedar and the top grade is called "No. 2 clear and better" which is what we used. Ours came without any knots and we have left it to 'silver'. To keep the look that you want will require quite a lot of maintenance.

Good luck.

Not that it makes any difference now but I would have had a supply in the dressing area instead of extract and I would have had a supply in the hall as I have here.

I don't think it is necessary to increase the ventilation level for bathroom use especially when your RH is so low. I would just leave the bathroom door open, any increase in humidity from baths or showers would be beneficial. Our system stays on level 2 all the time. As Jeremy says the system should be silent on level 2 and you should only be able to feel slight air movement next to the vent.

I was comparing skirting heating to radiators in a low energy house.

I can't see a real problem with that setup.

If I needed central heating in a low energy house I would consider skirting heating not conventional radiators.

Where are the intake and extract vents on your house? Are they on the same wall and does that point in the direction of the prevailing wind? Are you far from the sea?

@lizzie If you create a table based on the one I sent, you will be able to fill in the first four columns for your house before your technician arrives. For the first column calculate the volume of each room in cubic metres. For the second column just copy the appropriate air changes per hour rate for each room. From that for the third column you can then calculate the air flow rate per hour in cubic metres per hour. The fourth column just converts m3/h into l/s using the conversion factor of 0.277778. The last column is the calculated air flow velocity in m/s using the cross sectional area of the measuring device. Good luck .

It's also worth considering whether UFH is the best form of 'wet' heating. There's a lot more to UFH than just the pipework and it is less efficient than radiators or skirting heating. It does have it's advantages but I wouldn't say it was a no brainer.

If you have a small garden and don't like ivy, honeysuckle is a good alternative. We are also going to grow pyracantha along part of the fence, it is evergreen but spikey and the birds like it for nesting and the berries are a good food source.

For exactly that reason we decided to use a Genvex Combi 185LS in conjunction with electric towel rails in the three bathrooms. When the Genvex is in air heating mode it turns the supply fan speed up to maximum for around twenty seconds and then turns the fan down to around 70%. We can hear the fan on maximum but when it slows down it isn't audible. We have a small house, around 306m3, and the system works well for us. If the house were any larger the warm air supply wouldn't be sufficient in cold weather.

I am going to build a sparrow terrace this month and site it under the eaves on the NNE side of the house. A lot of boxes are positioned in the sun which can be a problem for young birds that only receive moisture through the food brought to them.

Do you grow house plants? They can increase humidity by transpiration.

@lizzie From what you have said I'm sure your MVHR is over ventilating. The RH in our house is always 40% to 50% and we have never used the boost button. Ask your engineer to set it up to use the PH air changes per hour for each room that are on the table I sent you. Maybe having a dog in the house adds another problem. Good luck