Home DIY

I feel itchy just looking at those photos.

They do look like they are just there to support the knee wall though. I expect @absurdbird has better insight though.

How is it ventilated, by the way?

You might start developing a damp problem if there's insufficient air flow.

Yeah thanks. I’m massively confused about why the mineral wool is against the sarkin. It is all over and has been for ~20 years with no evident problems. I’d like to rip it all down but can’t face the dust.

In terms of ventilation. Being a ~250 year old house when there is a breeze you can really feel it in the eaves. So it’s coming in somewhere.

The primer -Zinser or whatever you’re using ( I always have SBR knocking around) is to stop the new filler absorbing more of the water in the finish coats of paint than the surrounding existing paintwork, not to cover it with an opaque layer.

When filler isn’t sealed it can grin through - this is especially noticeable with paints with a sheen.

Yeah, I agree these aren’t structural to the roof.
Fine to remove IMO.
Is there a purlin visible the other side of the knee wall? Any cross ties?
I’m just wondering how the roof is constructed- there are so many ways and regional variations.

I feel itchy just looking at those photos.

Makes me want to strip off and roll about in it.

but can’t face the dust.

Yeah, horrendous.
Hooded Tyvek suit taped onto gloves and boots and a good mask.

And still get someone else to do it.

No purlin visible. We have collar ties visible at ceiling height though.

Could it just be roof rafters and collar ties?

Being a ~250 year old house when there is a breeze you can really feel it in the eaves. So it’s coming in somewhere.

The problems tend to arise when modern construction methods meet with the old.

Drafty old houses don't need to worry about ventilation as much, and the materials are breathable and porous.

Modern materials are much less so, and will prevent the older stuff from breathing / drying out.

Moisture can wick / pool, and you could end up with blown plaster, mortar turning to sand, rot and all sorts of other fun stuff.

I’m massively confused about why the mineral wool is against the sarkin.

Someone had the idea that it was drafty and cold, and decided the way to fix that was chuck rockwool up against it.

My mother, bless her cotton socks, was persuaded that the way to insulate the loft in he Georgian house was with polyurethane spray foam. It is not removable, has cause a damp problem that didn't previously exist, and has made it uninsurable and potentially unsellable.

Maybe I’ll just man up and take it all down, there isn’t loads I just can’t be bothered but I get your point. And it doesn’t make any sense to be there.

Maybe just some kingspan / other PIR instead - you can install it between the rafters with a gap between it and the sarking, allowing air flow from the soffit / eaves.

Could it just be roof rafters and collar ties?

Oh yeah, if the rafters are beefy, or not very long, or the pitch is steep, or the roofing material is light, or ...
Many ways to skin a cat.

Shallow pitch with heavy tiles/slates needs more structure.

I’ve taken one pair of ties out in my loft but I’ve built really solid/structural shelving from the purlins down so I’m not worried.

Drafty old houses don't need to worry about ventilation as much, and the materials are breathable and porous.

I wish our previous owners understood that. Every gap, vent or other old way of letting a house breathe has been filled with cotton wool and/or silicone.

Getting a little more technical, the difference between 123 and Gardz is the Gardz is thin like water and has no opacity but can soak into the surface of the filler and seal even the little pores where 123 sits on top a bit more because it has a bit more body.

This is great intel, and something only us lay folk would find out after throwing money at all the various products. Appreciated as always.

I have some bare hardwood interior window sills that will need painting. The plasterer recommended Zinsser Stain Block for those as he said it's shellac based. Does that sound right?

I think Cover Stain is alkyd/oil based.
BIN is shellac based - it’s the only Zinsser product I’m really familiar with, I always have a tin.
Either would be fine, I think oil or shellac based primers are still the best thing to use, I often use aluminium oil based primer on hardwood.
Your finish is only as good as your first coat, something something.

I have garnered a reputation for recommending Zinsser & Toupret! :) I'm looking for UK based alternatives but I let the rest of the trade do most of the job and then try the ones that are popular with a no nonsense decorators merchant in the local area. Plus a lot of discussion with other tradesmen over the years to find out what they like to use.

I've used pretty much everything that Zinsser make and they are a decent boot and braces option for most people but I do also try out more exotic paints for different jobs/reasons.

You're right cover stain is oil based and it's available in a spray version for touching up stained poly tiles in ceilings or just stained ceilings if you don't mind covering everything in the room. It's also necessary in some cases for blocking the stain from exterior pine if it's been completely stripped of paint, the other primers tend to let the stain bleed through.

BIN is the only one I don't use much these days because it needs meths clean up and I try not to keep white spirit and meths on site.

If your finish is as good as every coat you put on :) It's why I'm always banging the drum for Gardz, it was one area where everyone has their methods and I've tried loads but when you have to fill a crack running right through a white ceiling then re paint the ceiling it's the only product I've used where you will not see the repair after 2 coats of white paint. Of course getting a decent finish on ceilings is an art anyway.

Cover Stain or BIN. I would use cover stain because it's more useful for other things but BIN is thinner and soaks in a bit more easily.

If I’m putting a Tado TRV on a rad that currently doesn’t have a trv, is it possible to buy just the tail, or do I have to buy a shit trv and then butcher it?
I can mostly just find full sets through searching online.

Can anyone recommend a quick drying adhesive that still gives you a couple of minutes to position things but sets soon after? I've got some 6mm ply to attach to the ends of some units to cover the old unit, but it's awkward/ impossible to clamp so I need something that will set pretty quickly but not immediately.

Was thinking about the Soudal High Tack adhesive but worried it will set too quickly.

Will 38x19 timber in ~900mm lengths work for a deck or will I experience sagageddon?
Sagulator says joists at 300mm centres is acceptable, 450mm centres is borderline.

Is there a calculator?
I’m about to layout for a little 3.5 x 2.1m deck at Bird Villas.
I’ve got some 100 x 25 iroko left over from a job so I reckon I can put the joists on pretty wide centres but ...ideally I’d like 550

There’s also a manhole cover I’ll need to frame around 🙄

19mm seems pretty thin - the length doesn’t really matter but the joists will need to be pretty close together.

Oh, just realised 900 lengths mean either 450 or 300 on c.
go with 300.

I wouldn’t use 19x38 for a deck. If you’ve got loads of it already you could use it on edge with 5mm gaps between.

Sagulator is a well known one.

https://woodbin.com/calcs/sagulator/

Wickes sell lockshield valves for £4 or £5

Conveniently, they are the right size for the tado TRVs without needing adapters (15mm x 1.5 iirc)