Is the DIY Wiki a tad out of date regarding LED lighting ?

"Feel free to provide updates" is often the answer to such comments...

Last time the 18th edition section was updated was to add AFCIs. It could do with a section on SPDs (and possibly a dedicated article)

Almost certainly...

Which ones are you planning to write an article on?

Well, I would if I thought I had the necessary knowledge, but I don't, so I rely on other people to 'fill in the blanks'.

A section on exterior wall insulation would be useful. I would seriously consider having the east-facing gable end of my 1976 semi done with this stuff even though it has a 65mm cavity with rockwool cavity insulation.

The cold wind that arrived 2 days ago has a very noticible effect and I suspect anything that shelters the wall from the wind-chill effect is going to be beneficial.

Didn't you mention that you were going to DIY EWI on your house a while ago ?.

Wickes seem to sell the grey-black insulating panels, so presumably the outer mesh and render must be in-store too.

Sometimes even just doing the structure of an article can help - it makes the "blanks" more obvious to someone trying to fill them in. It also helps identify what information is wanted from the article - something that may be less obvious to someone that has a degree of expertise in the topic.

Having just completed an EWI project I may well do something on that...

I did. I started at the end of July, and I (mostly[1]) finished at the end of November... just recovering from it now! It was a fairly sizeable job and took quite a bit of effort - especially as there were quite a number of other jobs that needed doing in preparation in addition to the insulating and cladding.

I just had a look at what they have on the web site - and it looks like they just have Jablite EPS panels - but not much else in the way of all the extra bits. (and note that you might expect the insulation to be the expensive bit - but in reality it is all the extra bits you need to go with it that represent the vast bulk of the cost)

Many systems seem to go with an insulation panel then a mesh finish on the outside (sometimes part of the panel), that can be rendered over with a light weight render.

For a number of reasons I did not really fancy that method, so did PIR boards, then battening and feather edge style cladding over the top.

Did you extend the eaves? That looks to me to be the biggest PITA. Plenty round here don't bother and use a shelf to deflect rain.

And did you take the insulation below ground/above ceiling heights, as with IWI? I've never yet seen that done. Maybe it's too difficult, or has a poor return. Not sure.

Heavy with cold at the moment but I may start a page if I can find the energy.

I did consider it, and in the end decided that was going to be too much additional work to do at the time. However I did already have a reasonable amount of overhang available - typically at least 6" to the inside of the facia board in most places. I also gained ~20mm from hacking off the existing render. So by keeping the extra layer at just over 4" (60mm PIR, 25mm batten, ~18mm cladding (each board is only 8mm, but laid in a feather edge style makes the max thickness a tad over double)) it left adequate coverage at the eves.

I don't think there was anywhere I could go above ceiling. The loft space is habitable (converted in the 80's by the previous owners). Only the very top of the rear gable would count as above ceiling.

I could go below floor in some places - the house has a "skirt" on both sides which is below internal floor level (which is quite a way above external ground level). I have not as yet insulated that (I could - but am not sure if there would be much return since it is a ventilated (airbricks) and unheated space).

That sounds like a decent level or protection. I've not followed the 'EWI GB Disaster' story too closely but I'd bet that's the main point of failure. Some was done round here and it failed within a couple of years.

Hugely impressed by my neighbour who reroofed her house in about 4 weeks and extended the eaves 'while she was at it'. The gutters and bay looked to be two of the trickier jobs. She did have some help over a couple of days - but it took my roofers about as long for something similar (and no extended eaves).

I've seen pictures where they push the insulation up so it almost touches the tiles. In your case I suppose that would have to overlap with whatever you have in the loft space. Bit messy - can't think through how ventilation could be maintained.

An issue with retrofit - often a bunch of knock-ons.

One way of minimizing the total width of the insulation is to use two layers of PIR. This is how I insulated the inside of my North-facing lounge wall and the area around the front door.

The space in between the battens was infilled with 30mm PIR, and then 9.5mm plasterboard sitting flush on top without any gaps. If you did the same outside you would presumably have to add a layer of breathable membrane under the final cladding.

So now this (North) front wall has a 65mm insulated cavity(*) and another 80mm of PIR inside. Combined with a new suspended hardwood floor using 75x50 battens screwed into the slab and infilled with 70mm Quinntherm PIR, makes a huge difference to heat retention. The resultant floor height is about 12 mm higher than it was with the 1976 builders uneven screed. This is only a problem if I decided to fit a carpet, which would be tricky around the front door.

(*) The cavity actually stopped one brick course below ground floor ceiling height. Then there was a course of bricks laid edge-on across the cavity and then the hollow 9 inch blocks laid on top. Combined with a lintel that looked like an RSJ and the holes and gaps everywhere (hidden behind internal plaster and external cladding, meant for an abominal amount of air leakage and heat loss as originally built.

Because the upper floor is clad with plastic, it does not have a cavity, just very poorly laid 9 inch hollow blocks with *all* the vertical joints left open (grrrr). Something I discovered years earlier when I carried out a similar IWI job in 1993 on the two north-facing bedrooms.

Unfortunately back then 'celotex' did not seem to exist. There was some pink extruded polystyrene in the local BM's, but only an inch thick and *five* times the price of bog-standard white polystyrene sheets, which I used.

Back then if you asked for 'insulation' at a BM, all they had was fibreglass rolls, EPS or some sort of compressed 'straw' batts.

Houses with ventilated raised timber ground floors are tricky to insulate. If you have EWI or IWI to fix the (inevitably) 9 inch solid walls, you cannot overlook the heatloss downwards (apart from using a quality 80% wool carpet and thick underlay).

I'm not sure what purpose a membrane would serve. You've already created an impermeable barrier.

Looks like you've done a good job considering. My only question relates to ventilation. If the original building wicked moisture out through the fabric, you've now created something of a sealed unit. How do you deal with moisture generated inside your home?

I'm not sure it's that difficult. Simply fit PIR between the joists. The difficult bit I've found is around the edges. The PIR needs to go (say) 100mm below floor level. Fine if all's clear below the floor. But often there's air bricks, strangely placed joists, pier walls, fireplaces etc. Fitting impermeable materials against wood in an area with high humidity and difficult access is high risk . . .

I get the impression that many of the failures are the result of not taking adequate care at boundaries with the existing structure like windows, flues, and pipes etc, that then allows water ingress behind the insulation.

Also leaving uninsulated gaps behind external features fixed to the house like meter boxes, gate posts, soil pipes etc. Those can then create internal cold spots which attract condensation.

You also need to consider the effects on ventilation when you add a potentially impermeable layer to the outside - older properties would have got rid of excess internal moisture through the solid walls.

(something applicable in my case with solid brick walls - although my starting point was a building already covered in impermeable cement render on three sides - so in this case that ship had already sailed!)

Impressive indeed.

My soffits were pretty close to the under side of the slates anyway - so I insulated up to them. The cladding was then left about 10 - 20mm short so as to leave a ventilation path behind it (with perforated ali trims at the top and bottom to keep little beasties out of the space!)

Indeed it tends to be a process rather than one job that fixes all the problems.

In our case under floor insulation on the ground floor would possibly be one of the next ones to have ago at. Perhaps also dry line the the rest of the front of the house (where there is no EWI) - although that will also only have limited scope since much of the front exposure is actually windows / door anyway).

It's a modern 1976 house so any internal moisture just finds its own way out (mostly thanks to the hugely excessive air leakage anyway). I adopt the German method of opening all the windows for a few minutes occasionally anyway.

I also have an Ebac PowerDry dehumidifier and at the end of September I turn it on at its minimum setting and just empty the tank every other day-ish. My Lidl temp+humidity meter reads up to 70% by the end of a hot humid summer but over a period of a month or so (Oct + Nov) drops to somewhere in the mid 40's.

Don't underestimate the amount of dust and disturbance doing it internally. I effectively re-wired the house as well because of the need to extend the wires in the back boxes. 1976 t&e only had a 1mm sq CPC so I decided to fix that at the same time with a rewire. The upstairs lighting cables in the loft were exuding green gunge into the light fittings, another reason to replace it all.

Ah, stossluften - shock ventilation - yes, I do that. I think it's quite a continental thing. My Dutch relatives even hang out their duvets every morning. It seems counterintuitive, letting all the heat out. But it soon comes back, stored as it is in the building/contents.

I'm not quite that rigorous but when the RH is up I'll dehumidify in living rooms if it's persistenly above 65%. Never achieved mid-40s though. I've got these scattered around the house: