Iceverge

Am I correct in assuming the red line I've drawn is the top of the ventilated void? If so I can't see how you'll be able to put the telescopic vent in the "side" as the telescopic vent will be obstructed by the beam inside it. Can you post a picture like the first one but showing a corner of the building so we can see how far back the first beam is set from the 140mm wall? If it is hard against it you will have to have your vents outside the wall or else in the "end" walls.

@Nickw1982 How are the noise levels?

I've not heard of anyone having trouble with these slumping. I think @ProDave used something similar. Apparently the better insulating ones (Slab 32) are better to work with. Rockwool would be better acoustically and maybe nicer to work with but it's expensive. Blown in cellulose is my favourite however. It is how a wall or roof delays the suns heat passing through it in the summer. It's also called decrement delay or phase shift. Don't confuse it with overheating caused by poor glazing/shading choices. It's well explained here. https://www.greenspec.co.uk/building-design/decrement-delay/ You're right to ask. I make tons of mistakes and often think I know more than I do!. It's here to create a service cavity which allows you to run pipes and wires through the walls around the house without puncturing the vapour membrane ( in most cases also the airtight layer).https://foursevenfive.com/blog/the-service-cavity-making-airtight-construction-easy-2/ This membrane is important, it stops air moving through the walls taking moisture into the structure where it will get cold enough to condensate rot the timber. It prevents cold drafts blowing into the house. It must be carefully installed, taped with airtight tape to all windows and doors, floors and ceiling membrane. All penetrations the same. You should aim to have no holes at all anywhere. Effectively hermetically sealing your house. Contrary to cranky old chippies opinions, combined with proper ventilation, you will have a much more durable, healthier building. Normally clipped to the service cavity batten AFAIK. I won't pretend to know this. Maybe an electrician will be along to help.

I would just fit a conventional good quality one unless you end up with extract only ventilation. There'll be plenty of air in your house to feed the stove. No need to put in more holes. It does help. I'll try to show with some Therm simulations adapting my own 250mm eps cavity wall. An approximation of external wall insulation only. Total interior U value 0.49. Now with 200mm EPS in the floor. U value drops to 0.3 but still lots of heat escapes via the corner if insulation is not carried down. Bearing in mind this is with a wall U value of about 0.13 and a floor of 0.16 so the effect of the thermal bridge is dramatic. Look what happens when we carry the insulation 700 mm below floor level. U value drops to 0.2. A big improvement. The same but with floor insulation removed. U Value back to 0.34. Next I've added 1m of 100mm EPS horizontally. The floor U Value is now the same as with just the 200mm floor insulation and nothing externally below ground. (this is a simplistic example so they wouldn't perform the same in reality. BTW I've also accidentally removed the outer leaf here but it makes little difference) Finally I've done all I can to avoid digging the floor, Externally insulated with 250mm EPS 700mm below the ground. Included a 1m wing and added 25mm of EPS above the floor to take the underfloor heating pipes. U value is 0.27 overall. I'm going to make a crude estimation and say this is the equivalent of putting 250mm EPS in your floor and not taking any measures against the wall/floor junction. The lesson of all this is 2 fold, firstly if you can't or really don't want to dig up your floor there are other options. Secondly insulation is of limited use without getting a handle on thermal bridges. If you search for "french drain" I did some posts recently about them. I think everyone should have one. It'll be a pain with the insulation already installed and if you put in batt or roll insulation you'll never fix it right again after putting in the ducts. Hope this helps.

What the timber frame manufacturers suggest get through the regs using the absolute minimum amount of timber and in factory labour. I would like to see any results of anyone getting a satisfactory airtightness result from this construction. I'm happy to be challenged on this if anyone knows better. The timber is exposed to the full variables of relative humidity within the building as there's no vapour barrier. With a rigid insulation like PIR how does the subsequent expansion and contraction of the studs not lead to a leaky structure and moisture laden air coming into contact with the back of the OSB sheathing? How does the structure cope with PIR shrinkage? It also has poor heat protection for the timber clad areas. (brick exterior takes care of a lot of this otherwise)

I echo what @Thorfun said. Open panel, self insulate. Then add a vapour membrane + 45mm insulated service cavity and nail the airtightness. It's cheaper and more effective than adding more insulation. Easy improvements from here would be to increase to Frametherm 035 or 032 and then to increase to a wider main stud. Blown cellulose for the final win.

First things first. Have you made absolutely sure that no outside water is getting in anywhere. Leaking gutters, weeping pipe joints, exterior kept damp by high ground or vegetation against the walls A damp house will be almost impossible to heat and will cool instantly the moment you turn off any heating. Next have a look at ventilation. The house could well have the common but dual problem of being too drafty when it's windy but also under ventilated the rest of the time. We close all paths for air on a breezy cold night and don't open them later on. Hence a cold house when it's windy due to drafts and a damp house otherwise because the structure can't dry. The solution to this is mechanical ventilation that runs 24/7 and doubling down on airtightness. PIV is the beginning of the road with this MEV/CEV/DCV next And if you know about Enerfit you'll be familiar with MVHR. The ideal standard. Airtightness it the elephant in the room here. Suspended timber floor and (I guess??)plasterboard dot and dab over thermalite are dreadful for airtightness. This combined with what I wager is less than perfect pointing on the facing ston. The wind blow right through the house's structure. No wonder you're cold. My advice is if you are a competent DIYer is to go room by room and seal every gap with flexible caulk. Take off the lighting rose and seal where the wire goes into the plasterboard etc etc. It might sound ridiculous but every single crack that you could fit a hair through will make your house colder. If you're really keen make a DIY blower door fan from a sheet of OSB and a car radiator fan. It works a treat and many on here have done it. Re mastic around the windows externally and spend a day with a tub of putty and fix any holes in the exterior pointing. Beware making your house airtight without making sure ventilation is sorted though. It's a recipe for mould. You will need to take up any floor coverings and put down a membrane at the minimum over your timber floor. Preferable to insulate underneath also Adjust your windows and doors so they seal perfectly. Once this is done you can tackle insulation but I wouldn't begin this until airtightness is done as it won't make much difference while you're living in a collander! Welcome and good luck! P.S any photos always help the case.

ventilation airtightness insulation in order. you could have issues with moisture otherwise. make your own rig, a sheet of OSB or plywood and a car radiator fan connected with some wires to a car battery.

250mm eps blown bead cavity here. 0.31ach50. wet plaster inside and out. It’s certainly doable but there are easier ways to get to passive standard. Look up the denby dale house on you tube and @tonyshouse blog. I found them both very useful.

It might be structural. proceed with caution.

Just add more insulation. PHPP makes it easy to see what the best trade off is. Passivhaus is definitely easier to satisfy with a larger squarer building but you can get passivhaus performance in a compact cottage without reaching the passivhaus levels. https://passivehouseplus.ie/magazine/insight/the-small-passive-house-problem-a-solution

It's PITA to fit 100%. More often than not it's not done perfectly leading to thermal bypass. It's expensive. Poor decrement delay.

What stage of construction are you at? Some photos would help. I really like double stud walls but like you say it's like building two houses. Concrete blocks are very cheap in comparison to timber. You could make a jig for setting the blocks if you are a competent chippie. Eps bead insulation and a layer of sand cement plaster inside. You'll have a cheap wall. PIR has no place in a timberframe wall. I maintain board insulation should only be installed on a flat surface like floor slabs, ewi or warm roofs. However send a pic or a drawing and it'll paint a thousand words . ☺️

I haven't checked. I was careful all along to make sure the sums of the openings added up to equal or greater the 160mm duct area out of the MVHR unit. In any case I doubt it. Flow is only really severely throttled at the terminals.

Go for it if you have plenty of funding. Passivehouse gets very difficult if you make lots of junctions and lots of external surfaces. It can be done but it'll cost you. https://passivehouseplus.ie/magazine/new-build/vernacular-passive

AFAIK most suppliers will make a door to suit your opening. One manafacturer (https://www.modernupvcwindows.co.uk/) says minimum 700*1900 to maximum 1050 * 2250 for a pvc door. I would err toward the wider sizes. Easier to get furniture etc in and out.

Tops. That jobsite is immaculate. The system reminds me of methods used in the States. Did you run any pipes in the walls?

Very interesting. How did they blow in the cellulose? Did it require holes to be cut in the plasterboard? I assume services were threaded through the i joists? Do you have any pictures with the wall "open" .

We're in now with 7 months. I've never been chuffed at the noise of the MVHR at night in the bedrooms. We had a flexible acoustic silencer from BPC but it's been of limited value so I decided to rig my own scrappy attempt. Firstly it's in an awkward corner so I had to go for an irregular shape. MDF and airtight tape was the order of the day. Some discarded foam formed the maze for the air to transit through the first level. All held in place with spray adhesive. You can see the entry hole at the left of the box. Capped with another layer of foam. And a sheet of MDF all taped up shortly afterwards. A hole for the air to enter the second layer. The second story was a little different. I drilled 160 18mm holes (yawn, boring!) and offset them to try and diffuse the noise a little. The first layer seemed good at getting rid of the 375Hz and 7500Hz noises that my phone recorded but not the 53Hz, after some googling of car exhausts the many small holes method seemed like a good idea. Mostly fingers crossed and little science involved. I shoved it into the corner and connected the ducts up. (Supply enters straight from the top of the MVHR unit and exit is above it in the roof. I might enclose it at some stage if I can be bothered. And hey presto. I took the opportunity to use my iPad to do a sound level recording before and after with the unit on boost. Pretty pleased with that. All we have to do now is enjoy the sweet smell of glue as we drift off into silent slumber tonight.

I cannot guarantee the formula is correct but it seems to be ballpark and i’m delighted someone found it useful. You would need a 25kW combi boiler to keep up with that flow rate. A heat pump at say 8.33kW ( for easy sums) output will buy you a meaningful amount of extra hot water. It would reduce your effective draw on the stored energy in the tank by 1/3 to 8l/min giving you 30 minutes of continuous showering. If you were to space them out over a period of an hour you could have 4 x 10 minute showers, In a situation of exceptionally high demand,like with guests, you could have the tank at a higher temp or engage a couple of immersions to give you even more capacity.

Welcome welcome. I love the sound of your project in a smashing part of Britain. If you can spare the effort, get a copy of PHPP. It is a tremendous learning tool if nothing else. I would employ a proper passivhaus designer who takes overheating seriously and builds in proper measures to counter this passively. If i had the choice again I would build like that, timber + cellulose, ace. Blown in insulation on site wins for me. No waste, No settling in transit. You could get some joiners and build panels in your shed no problem. A couple of single story houses that caught my eye browsing the web. Cousins River in the US. https://www.gologic.us/1700-model designed by https://opalarch.us/portfolio-item/cousins-river-residence Old Holloway. https://passivehouseplus.ie/magazine/new-build/deep-green-passive-house-defies-all-weather https://oldholloway.wordpress.com/ Your chosen build method sounds like a couple of projects from Mike Whitfield and Dempsey Decourcy. Ty Pren https://passivehouseplus.ie/magazine/new-build/the-west-midlands-eco-house-with-no-energy-bills Good luck!

I installed one of these as I wanted to keep the ductwork tidy inside the house and have minimal run of "cold" ducts inside the thermal envelope. https://www.proair.ie/products/proair-fex-terminal/ In essence it is a bracket for 2 ducts and a cover which ensures no interference of airflow. However I recently left the cover off for about a week while I was painting the house. This left two 160mm ducts separated by only 50mm. All through that time we didn't notice any difference. When I cooked a curry I thought maybe we might get a whiff in the bedrooms but zero/nada. The space behind our house is very open with no nearby buildings. I haven't seen interference between ducts in real life. I imagine that if you are not venting into a small enclosed alcove there's little risk of ever suffering from intaking much exhaust air. Happy to stand corrected by anyone with any evidence of it happening.

My mantra for proceeding. 1. Sort any bulk water issues. 2. Ventilation (preferably continuous mechanical, ideally with heat recovery) 3. Airtightness (cheap and hugely effective) 4. Improve u values. (Including windows) 5. Consider your heating system. 6. Renewables (PV)

There are options for a heat pump with only ducting to the outside, No need for an outdoor unit. https://www.jouleuk.co.uk/victorum-exhaust-air-heat-pump-pre-plumb-system/ To be honest I think your idea is fine. You may struggle to get large flow rates with an instant water heater, but if you can live with it you will avoid annual inspection charges which will forms a large part of your set up as is. If you have a record of your average usage with gas it's simply a matter of doing the maths for electric and/or heat pump.

A print out of the buildhub "brexit" thread, although it will be still running by then, probably no closer to coming to any conclusions.