G and J

When, as an adult, having moved away from the smokehouse that formed me, I helped decorate my parents living room - I started by washing the ceiling. I could not believe what was coming off. Perhaps that’s why I’m now a fresh air freak (who subconsciously likes brown).

Good plan. I like the gently warming background smell of smoke. As a child in the 60’s I was a three packet a day passive smoker so I guess it brings back fond memories. Well, memories anyway. Actually by Jove that’s it. I don’t want a passive house - I want a passive smoker house - everything needs to be various hues of brown. Our design is finally complete!

Hang on, I was asking a question, not stating what I know to be true. I think it would be great if the person who designed and/or signed off your design shared their view with you. Remember, finding an idiot like me on the net that just happens to have a convenient opinion doesn’t make that opinion true. And if the guys in those areas have put in a rule it will be fir a reason, i.e. some bad experiences, so that rule indicates to me that it’s highly likely that at some point in the past someone in the know believed that such cavities need active ventilation. What did said info source say about venting at the bottom?

You might be thinking of my baking skills. In a moment of inspiration I realised I should plumb my oven directly into the MVHR. 😕

I think the final answer will be to simply putting a big standard recirculating cooker hood in, together with a grease filter on the MVHR extract vent for that room. However I do like to work through the options to hopefully make good, informed decisions. The emotionals are difficult here for me. I’m a fresh air freak and currently live in a well insulated wind tunnel, so major purge type ideas resonate even if they are not really needed.

and then if I add a second fan and heat exchanger I will have invented the assisted airflow energy retention system. This time next year Rodders, we’ll be miwionaires…. Maybe not….. 😕

So I need: an in-line fan. two mains operated dampers, preferably return to closed if power is removed for simplicity. one of these vents to the alley above head height, ducted via the auto-damper (tm) to the collector above the hob via the inline fan. the other inlets at knee height in the alley and feeds ducts which outlet into the room at kickboard level maybe. Hmmm, still much opportunity for imbalance , but it mimics opening a window and that’s ok according to the PH guys. Just wear a big coat when cooking in winter….

We fry very little and still over time there is trace evidence of grease build up on our stainless steel cooker hood, so I take it as a given that there are nasties to be ejected/captured. We are not having a hob in our kitchen area as it is part of the big living area. Instead a hob will be used in our utility room, one wall of which is external and has a narrow and rarely used alley next to it, so perfect for dumping stinkies. So my thinking is maybe wall mounted fan ducted to collector above hob. But when this runs does it unbalance the MVHR? The direct air woodburner is in another room but will it blow back if one opens the door to load wood when the extractor is running? Do I need an auto opening inlet also in the utility room to balance things? Will the extra holes in my otherwise nicely air tight house undermine all my careful design/taping/etc? Yours truly, Worried of Suffolk.

Will this link work? https://www.ubakus.de/u-wert-rechner/ It takes a bit of getting used to but by looking at the build ups others have posted it falls into place fairly quickly.

So I’ll get over £4K back in used fivers from my MCS installer then. Cool. On a more serious note are those close to today prices? And which ASHP is that based on?

How far apart are your two properties, wall to wall? And what did they get you to do?

Understood. For us however the whole calculation is skewed by the grant which I’m expecting to substantially pay for our ASHP.

We’re planning a cold roof, and whilst I’ve not read up as much on this as perhaps I should, I’d gathered that counterbattens and ridge vents would mean the tiles and the solar pv panels will be nicely ventilated behind. Given the airtight(ish) envelope of the house that should mean that little moisture found it’s way from the house to the loft, and what does find it’s way in there will escape through the breather membrane. All that I think means no soffit vents so no plague of insects in the loft. Does all that stack up?

Unfortunately we are cheek by jowl (1m one side/ 1.5m the otherside) between 2 1920s timber framed properties....BC won't wear it.

It looks good, but we are in a an area(residential) that was up in arms about cladding, even though the silvered timber will be in keeping with the boat yards in the conservation area about 500 yards away......our planner was supportive, the neighbours not so much....

Thanks @HerbJ that' kind. The problem we have is finding something that can take both the fire treatment and the coating that accelerate and even out weathering to silver.

Would you be happy to post a picture? And am I right in thinking you used thermopine on your deck.....a picture of that too would be fantastic......... We are really impressed with Russwood and its an important element of the build for us only snag is they only offer either scottish larch in b on b (we weren't originally thinking of that profile) or thermopine with both the burnblock and sioox treatments.....ta

So, an installed window with a total of 1m2 showing (frame and glass) would lose 0.712W for each degree in temperature difference. I’m assuming Uwindow means the overall u value of the window when it’s installed. if Z fraction of the window is glass then: (Z x 0.522) + ((1 - Z) x 1.132) = 0.712 Therefore: (Z x 0.522) + 1.132 - (Z x 1.132) = 0.712 so…. Z x (0.522 - 1.132] = 0.712 - 1.132 = -0.42 thus…. Z = -0.42 / -0.61 = 0.689 AKA 68.9% therefore : 0.689 * 0.470 + (1 - 0.689) * 1.132 = 0.32383 + 0.3521 = 0.676. Wow. I did it! Do I get a sweety?

Yes I do! Go on, pick one window to use as an example. I’ll be sitting round waiting for heavy drilling equipment to come available (yep, the dentist) and doing a worked example will distract me.

Having been reading about this stuff incessantly of late I think I know how this works but how about you post some dimensions and I’ll use it as a revision question and work some numbers? (and in the meantime I’ll revise!)

Given what I think is built already I guess you are limited on your options. As your VCL is under your inner PIR then channeling into that is messy and a pain but won’t affect the VCL, so I guess that sounds ok to my limited understanding as long as you never puncture the VCL and don’t go too deep too often to undermine the insulation. I wonder how much ventilation is ideal for the void between stone and frame? Given that you have a breather membrane between that void and frame I assume the frame dries with moisture vapour travelling into the void. The stone itself may not be vapour permeable but the mortar may be plus cold stone will at times be cool enough for condensation to form on the inside face to either soak into the mortar or run down to the weep holes. Perhaps whoever designed the build up made an assumption based on the above rather than ventilation - can you check? If you do need that cavity to be ventilated I would always look to close with metal mesh but how you get air in at the bottom defeats me. I’d be interested to hear the resolution.

@nod PS, congrats on moving in! Hope it goes well.

17 years after we finish our build our warranty paperwork will have long since been firelighters, the faded PassiveHaus Certificate will still be proudly displayed in the hall in the vain hope that it’ll help the valuation for the lifetime mortgage which we will need to replace the old wheeled campervan with a new thermonuclear (food waste based) powered hover van with integral health suite and coffee maker. You never know, PH might become trendy and help sell in the future…

Architect just had a case where a 100mm over height was complained about and they had to re work..........one of our neighbours to be would notice.....they did a lot of measurement and comparisons in their objection and are peeved their objections were all ignored.......we may have this issue as alternative to a slight kick in the upstairs or lower ceilings in which case we'd do what @joe90 did and lower pitch very slightly .......for running of mvhr and cost we want to use 304mm posi joist, architect had assumed 200mm and we didn't check...... ho hum

Ah yes, thanks..... should have said we do want actual wood, which will have to be factory fire treated and therefore the sioox coating (which we like) is not effective. Also should have said the ayous would be thermally treated. Plan is just to let the wood go silver, so knot holes etc (half rendered) is not the look we were hoping for.