renovator123

Interesting, thanks. We are facing similar issues. Diathonite is actually a range of products with Thermactive being IWI and Evolution being EWI, plus extra products for areas with a lot of salt crystals, a tanking solution and top costs. They do a top coat cork spray which can be colored and is less prone to cracking and better able to move with minor movement compared to most render. I think we have given up with CorkSol, U value is not a good and they don't seem so good at getting back to you, and unsure of the quality / consistency of it. Another Diathonite EWI case, the House at the Northern Gate has it too (far North of Scotland and coastal). https://www.fca-magazine.com/features/product-specific-features/1396-ecological-building-systems-cumbrian-period-property-overcomes-issues-of-damp-and-mould-in-major-renovation

I live on a hill in one of the wettest parts of the uk, but the water runs down the hill into a river and French drains are typically as part of that, it is not such as issue with the type of ground and the fact it's so steep - it would be an issue if we had chalk ir clay but we don't. It drains without a problem. DPCs are perfectly good when you have cavity walls and a fairly modern build and you don't have any rooms below outside ground level. It's not exactly practical to expect a DPC on 600mm limestone and cob with render and gypsum plaster to keep the wall dry, especially not when you do not have a floating floor or real foundations - we've been down that route and not had it work. So the focus needs to be on what materials work for the existing building and the limitations of it. Keeping 100% of damp out is highly unlikely so going with traditional but updated building products means moving further to vapour open, and MVHR (heat recovery ventilation) will be reducing any excess humidity further, although I doubt we will see damp on internal walls in the same way later.

Lime is extremely alkaline which discourages fugus/mould/rot but the additional breathable means the damp has somewhere to go (via diffusion) which right now it's the case with the concrete render slapped on the external walls. Externally it will be coated to keep out driving rain.

Yes about the lower walls, something not so vapour open it needed for the lower part of all of this, I should have said. Diathonite Demix and tanking are needed for the bottom 30cm+ for at least some part of the house given about a third sits on a concrete slab over rammed earth and house is 1830s and has never seen a DPC. By "breathable", think "vapor open". Figures for vapour permeability by diffusion and air tightness values are available for all the materials mentioned, although some (foil quilt and Supasoft) have to be filled in specific ways for EWI - supercoil have a breather quilt for instance. Currently we actually have some damp in a fully internal supporting wall coming up from this. Hopefully we will be getting this resolved as part of the work. The electric back box for unused sockets have rusted a second time after having measures done to fix it before.

The walls are nothing close to level so a flexible insulation allows you to fill any gaps and level things out. EPS or other boards must have the gap between them and the wall fully filled. It's a period house that was built as both vapour open and breathable and keeping it that way it's going to cause its less problems.

Any suggestions or feedback for comparing breathable EWI options for a home aiming for EnerPHit (U 0.15). These options we are looking at: * Diathonite (clay/cork/lime) * CorkSol / SprayCork - how does it compare to Diathonite? * Wood boards eg Steico, Gutex (Pavatherm prices seem crazy) - durability? Bowing? Water ingress? * Supasoft (recycled PET) * Superfoil is advertised as breathable All seem very similar U value, prices vary a lot and Diathonite installers are hardest to find. We have ruled out thermafleece wool for reasons I won't get into here. This is to go under render (existing concrete based render is cracked and will be removed first), for an old house (500-600mm solid walls) with no damp proof course. IWI we have ruled out due to construction/layout and internal issues. It's a semi with very limited space on one side (under 100mm thickness needed). Anything extremely durable and really good for non-coastal but very windy area would be good.

I'm wondering about your EWI options- do you have a price per sq m for Diathonite, and have you had difficulty finding an installer? We are also looking at breathable EWI and options seem limited- although Diathonite looks excellent it's very expensive. I wondered your thoughts on CorkSol / SprayCork, or wood eg Gutex / Steico for EWI instead? I am not sure about durability of wood or about the ability to keep it dry when render over it will crack/decay sooner or later. We had calculations done for EWI using Diathonite, giving approx 57-60mm thickness (evolution, agrathem, etc) over 500mm stone but have recently found some solid walls are not uniformly that thickness, which affects ability to reach EnerPHit U values. Diathonite is similar in U value to rockwool and supasoft/thermafleece options which leaves me wondering about value.

TL;DR: Internorm EnerPHit prices above Windows approx £700-1,000 each inc VAT, fitting, removal of old, larger windows would likely be cheaper per sq m. Internorm only do single panel windows (glazing bars are an option) and only tilt and turn. Doors were in excess of £5,000 inc VAT and fitting, with only the HF410 model able to made in the shallow height we needed for retrofit, and us having a custom design. With no porch or conservatory on the house, the doors have made an incredible difference. Door designer prices are online: https://uk.internorm.com/internorm-door-designer/ Thumb turns & split spindle were fitted after by installer included in price, which were Winkhaus - amazing for keyless emergency exit, and keyless locking from inside without risk of accidentally getting locked out. Trickle vents - England - current UK regs state trickle vents are needed, clearly not suitable for EnerPHit or Passivehaus - but this regulation has some exceptions including certain other ventilation methods. https://www.gov.uk/government/publications/ventilation-approved-document-f

Some prices are specs... we went with Internorm and the quality is excellent, really noticed the difference and they haven't even finished installing so it's not close to air-tight. Velfac V200E we also looked at - prices similar to Internorm. specs: Internorm Retrofit Timber/Alu Argon filled triple glazing 48mm (4b/18/4b toughened/18Ar/4) HF410 windows, 0.71 W/m2K stated, calculations were 0.73 to 0.84Uw HF410 doors, 0.73 W/m2K stated Doors had to be custom due to height, with 1/3 triple glazed obscure, 2/3 timber-alu. 9 windows, total 7.96 sq m 3 doors, 4.85 sq m with unusually low height that was unavailable from all major sellers (Solidor do Tinidor but no other big firms do). Dec 2022 price £14,435 excl VAT £17,320 with VAT included Fitting was all thermally broken eg compreband to our solid stone walls (EWI is planned). Extras: * Removal of old, retrofit, * 2 thumb turns and split spindles on doors * Hirest weather resistant color * 1 window obscure glass + Full fitting including removal of old and scaffold brought up * Cat flap fitted in 1 door * Presumably a charge for overnight accommodation (2 people, 4 nights) and travel due to distance Final cost: £24,342 incl VAT - May 2023 (discount of about 5 or 10% at the time) (£17,320 excluding 20% VAT). Skip costs extra. Not a single supplier in our county was willing to quote for any EnerPHit standard spec from any manufacturer so travel/hotel bumped our costs. Green Building Store wouldn't do fitting for their windows and doors and neither would local tradespeople. Well worth it but we absolutely need a HVAC for condensation since extra insulating the loft. Cat has been sunbathing near a window ever since it got replaced and the heating is on noticeably less despite it not quite being finished yet.

Do any of you have installation quotes given separately, especially for smaller windows or part-glazed doors? Those locally only want to sell UPVC (we want alu clad or hardwood/ Accoya), and withdrewoir U values. We are having a nightmare trying to find fitter for retrofit for Green Building Store, or anyone to fit - looks like all existing Passive Houses in the area were new build or full refurbs done by a single builder which isn't possible for us. We did find an Internorm fitter but Internorm's reputation is poor and £5,000 per door (on website) when you need 3 doors is ridiculously beyond budget. Any ideas on window costs? What are we looking for in a fitter, who would likely be doing their first fitting involving thermal bridging prevention/ insulation? * Joiner, or carpenter? * Crane or lift, or is scaffold manageable? (No large upstairs windows, will need partial road closure though it should be ok). * What is needed for insulation measures? Doesn't seem like much info is given on green building society website. It's a rural area so anyone fitting nationwide or English/Scottish borders would be appreciated. At this point, we are over a year into trying to get windows while patching up the increasingly rotted 1980s ones with sealant, plywood, etc, and hoping they don't fall out. Nearest experienced builder and fitter has 12-15 month timescale, which takes us past our expected heat pump install. As with OP, prices are significantly higher than previous threads here. Internorm and Green Building Store supply only £12,000 - £15,000 including VAT for 3 doors (2 part glazed), 7 windows of 11 sq m. No fitting estimate at all. Things tried so far - Green Building Store currently short of fitters and suggested someone we already knew about with long wait list - Internorm don't do supply and fit for renovations, second nearest distributor quoted for supply only with 100% down before delivery which is too risky - Asked a local carpentry / window making firm to quote but they couldn't give accurate U values and ignored our specs and just went with their regular (poor) offering. - Composite firms also not an option for doors since we are below minimum height (low ceilings so unavoidable), they don't have the U values although we did look at Tinidoor who cut down composites but no fitters in this area

I think we will have to see on MHVR after windows are in, depending on air tightness given it's retrofit. Thank you all.

Hi. We are in the process of renovating with the aim of getting close to EnerPHit standard. We have a large bathroom with small shower extractor fan extracting through loft area to gable end wall, and would like to keep shower light. Currently the room has fairly new argon-filled double glazing with 2 air vents (the only ones in the house), and we slightly open windows during or after showers to reduce condensation. We also sometimes use an other bath clothes drier with air vents open. Main concerns are: * low budget * reducing condensation after bath/shower or when drying laundry, without heat loss * reducing heat loss from shower extractor fan into attic What are the options here? I have seen decentralized heat recovery units for walls, but can these be combined with existing shower fan? Are they safe to place in shower enclosure, which is by far the main area of condensation? Any concerns about length of ducting? Removing the fan from the shower light but adding an additional ceiling extractor fan using existing ducting might work. Shower fan is perhaps 60cm from gable wall of house (plus about 60cm thick wall), plus there is attic ducting, mainly above level of insulation due to avoiding fan overheating plus height of external hole/grill. Outside temperature is almost always above 0C in the day in winter, rarely below -10C overnight. Tumble drier is out of the question and laundry is dried on washing line when possible, but it's a rainy climate. (We will not be doing a single/whole house MVHR due to difficulty with layout/age of house/disruption).