Gordo

It’s not an issue if the wall is far enough away from boundaries and not supporting a fire resistant element.

Past your bed time

That’s where it can fail. Not a problem if left alone. But uncork that bottle and you can have a handling. I have blown fibre in mine (not my choice) and know there are voids now after 20yrs. Obviously some air is getting in through facing brick and disturbing the blown fibres. Not much I can do about it now. Bit annoying tbh

Don’t quote me but I think you need 1/2 hour fire resistance both sides of external wall. I assume that % windows are within that allowed relative to the distances from relevant boundary. Otherwise the BC officer would have mentioned concerns about % unprotected areas. So you just need to demonstrate that your makeup achieve 1/2 hr FR on both sides using manufacturers declarations such as the British Gypsum whit book

Yeah for a smaller extension it’s more expensive. I wish all brickies were like you, but in reality few are and those that are wouldn’t be the cheapest quote I’d guess

I understood the batts cavity wall insulation the strands aren’t so random but oriented vertically to reduce the risk of water penetration. I would imagine they are treated to some form of water repellent. I could be dreaming this last part tho lol

You won’t get much for £150 other than generic details and specifications I should imagine. Just use the planning drawings and your own generic details and specifications trawled of other drawings, cut n paste like. Wouldn’t suit a bespoke or unusual design/specification obviously.

The difference here is you aren’t providing a service. BCO are and if they offer advice they can be found in law to be accountable for that advice. That’s why mount talk little or carefully chose their works to steer people towards the correct choices But there are many less clued in who do

They may do. But they are not supposed to take on the role of a professional advisor / designer where they could be liable for any adverse issues arising from such advice. LBC duties are to inspect and raise pertinent concern for others to address.

100% agree. I always recommend pumped beads insulation as on balance believe it is the best option. I have seen so many cavities with built in insulation with gaps, not uniform, mortar snots on top of insulation etc. most trades are paid on quantity not quality and with no or poor supervision we get what we get. Then when you are looking for quality the trades default to what they have done or seen done where quantity is king and think you are expecting too much of them. Most speculative builders the foreman hardly leaves his hut to see what sub-contractors are doing as he knows what he will see and if he complains it isn’t worth it to him. He probably had subcontractors forced on him by the bean counters and would struggle to replace them if they left and the next crew wouldnt be any better. NO ONE REALLY CARES. They all say they aren’t going to be living in it and won’t be pay heating bills. There’s no incentive to do any better. Everyone thinks Building Control or NHBC are their supervisors Hahahaha They are often turning a blind eye too now for similar reasons to foreman. The number of times I’ve left a site shaking my head, thinking “What a shit show” the industry has become, and that is with blinkers on. The whole system is broken. Unless you do a self build and try your best to work around it or get a small hands on contractor who you can trust to do same. All more expensive and time consuming if it’s worth it to you.

That’s it. Works a bit differently to others. But quite usable. Especially if you pay. Don’t use it much as I prefer computer for cad

DWG Fast view is usable cad app for iPad. Free version has most of the stuff

Wow that is low for a regular house. spec of house would be interesting. High performance windows/doors? 300 - 400mm loft insulation? MVHR or just passive ventilation? Unknown/known air permanently? Form of house IE bungalow/chalet/house basic rectangle or intricate? What is target/ actual internal temperature Thanks in advance

Potentially but unlikely, obviously a condensation risk analysis should be done to avoid this problem. Like anything I guess this may not be done or not to spec or with poor workmanship. Over 12 month cycle (unless the moisture is trapped) if the element make up can breath it shouldn't rot. Persistent damp is the concern IMO

Good point, there is that to consider. Hopefully the airtight VCL and breathable layer does it's thing 😁

That's good, you have made your choices and with proper maintenance and a balance MVHR with room sealed stove there is unlikely to be a problem.

Think of it as a sealed bottle. If it can't escape the air pressure just increases some until an opening is created. If there is some leakage (there always will be) through imperfections, the excess air escapes. Better that than negative pressure that sucks in cold unfiltered drafts, IMO.

Yeah rigid PUR insulation and like isn't ideal for a curve, but if depths limited may be only way to achieve acceptable U values

I think you should read over this a few times then make your own conclusions. I would advised from research and common sense to slightly pressurise house from MVHR, but you do what you like based on your research. The carbon monoxide and particulate matter in your room won't affect me.

Why increase the thickness of timbers? If you lowering plasterboard slightly just use insulated plasterboard with say 25mm PUR lining. Then 70mm PUR between existing rafters or whatever to leave 50mm ventilation air gap. U value for these iminimum insulation thickness likely less than 0.18 tho.

Wise words. All this stuff is supposed to be maintenance checked including MVHR & stoves. A lot of stoves get once over every few years I’m sure. HETAS etc say MVHR is supposed to be have flow rates checked annually and ducts cleaned (lol dead on). I doubt many are checked following commissioning. I wonder how sanitary they are after 10 years. Interesting as I never thought much about this before. TBH the MVHR controls are mechanical dampers that are adjusted and fixed in position so shouldn’t need adjustment I guess. Ducts are bound to be lined in bacteria laden dust. Maybe just the extract ducts as filters should protect supply ducts

As a rule a room sealed stove in a room with a supply vent should be safe but even safer if overall the house is slightly pressurised I would be more concerned with an non room sealed stove and look for a "flue gas interference test" as proof. There were concerns raised about the risks when refueling which is OTT IMO. Similar risk with an open flue solid fuel effect gas appliance. But your gas fitter should check draft

Agree 100%. But you got to love a log stove

Here’s an extract form HETAS guidance regarding MVHR. For @JohnMo benefit so he knows I’m not just making it up. There so many reference materials out there. I can’t think of any benefits in opting for overall negative pressure MVHR

I think what chatGPT was referring to here is the pressure within the flue rather than the room. As a neutral or negative pressure in a flue is necessary for safe operation ie gasses will not escape