Victorian house issue

I'd get spark or in now it will save him a lot of time not having to chase boxes in which ever way you go

 

2 coats sand and cement then skim. Stick moisture inhibitor in the sand and cement mix to be sure...
Definitely do all your tracking before plastering.

 

Hi Sam.

What I would do, I think, is to rake out all the loose and powdery mortar from between the bricks to a good 15mm depth. Then drill all your backbox screw holes, fill the pointing behind where the boxes will go with mortar and screw them in to place.

Then get yer sparky to run the cables down the walls to the boxes inside flat ducting - the stuff you tack to the walls. Plaster with cement render with added waterproofer thick enough to cover the ducting - around 15mm? Get the finish roughly flat and level, but no need to get it smooth - this can be DIYed.

Once set, D&D foil-backed p'board to the internal walls and insulted p'board to the external. Even the thinnest IPB - around 35mm overall - will add a significant level of insulation to your house.

Ie - if you don't take this opportunity to add insulation to your external walls, then you are a very silly boy.

 

Why do you think it needs a sand/cement render? damp? stabilise? I'm working on an edwardian house project which has also gone mostly back to bare brick. The internal leaf of the wall certainly isn't the neatest brickwork, and the lime mortar is certainly soft, but it's stood for 100+ years and of course the internal brick takes most of the load (wall plates and joist ends are onto/into the internal brickwork only). I did re-set a few bricks which were very loose and could just be pulled out (but there again they obviously weren't doing anything load-wise)

In my project I'm fitting insulated PB to all external walls. Mostly 60mm insulation (72.5mm total), although only 27mm total thickness XPS backed PB in the stairwell/lobby. This is mostly dot and dabbed + some mechanical fixings. Obviously backboxes for the thicker insulation have to be stood off the brickwork, and I've used wood blocks for this to bring the 35mm backboxes out flush.

If you are thinking about sand and cement for damp protection, I'd be thinking about where that damp is coming from first. In my project there had been lots of visible damp on the walls, but this appears to have been mainly condensation. We have now concreted/insulated the floors which were previously flags on sand or suspended with no oversite over the bare (slightly damp) earth beneath, plus old fella who lived there only had a coal fire and dried all his laundry in the one room. Now the house is empty and the plaster has been mainly stripped its absolutely bone dry. If you are back to brick, I would think about insulation - the insulated PB also incorporates a vapour barrier.

IMO condensation is a big problem in older houses, because we tend to want to run houses warmer than they were when built (allowing more water vapour to be carried in the air), do lots of water-vapour creating things - cooking, showers etc, and then seal them up with less ventilation (DG windows, blocked up fireplaces). All together mean that the air inside easily gets loaded with water vapour which will condense out against any cold spots - particularly external walls - and cause damp issues.

 

That's the general idea.

There will certainly not be an issue covering the back boxes when using insulated p'board 'cos it's thick enough.

Even on the internal walls with normal 12.5mm p'board, once they are D&D'ed on, you are looking at 12.5mm + 12-odd mm dabs and the 12-ish mm layer of render = deep enough to cover the box (yes, the boxes come flush to the front of the p'board).

When I refirbed my bro's Victorian hoosie many many moons ago, I was so appalled at the state of the mortar between the (very porous) bricks that I did what I suggested above - rake out a good 15mm (possibly more!) and tacked 15x10 timber battens vertically as my render guide, packing them out if needed to get them pretty vertical. I then trowelled on my render mix with waterproofer, working it right in to the 'pointing lines', and building it up until it was flush with the battens. Even tho' I'd thoroughly dampened the bricks first, they still absorbed a lot of the mortar water so I was soon able to level the render off using a timber batten across the guides - it scrapped the excess mortar off neatly.

I was pleased by the strength and security added by the render, as well as effectively sealing off the inside from penetrating damp.

I then simply multifinished on top, but wish now I had added insulation to the exterior walls.

Since you may be D&Ding your walls, you don't even have to be neat with the cement render, 'cos the D&D will cope with large wobblies.

 

I am assuming you have a cavity wall and not solid.

While you have the house back to brick, it's time to check out for the real problems that might need sorting - wooden lintels with woodworm, rotten wall ties, (you could install resin/remedial ties from internal at this stage if necessary) rotten/wormed joists (much easier to replace with no plaster on the walls) and other timberwork. Particularly look out for dry rot (where the wood gets sort of square cracks and goes crumbly). We had worm in floorboards - replaced, and 3 bedroom floor joists had some worm (funny how they only like some timbers). Core sample showed it was not extensive and only in the outer 1/2" so as they were a good size (8x3), only a few affected, I chose to just dose them with worm treatment to save the plaster cornice below.

You also have a good opportunity to sort the windows out if they need it. Quite possibly you have, or had sash windows. How have the window reveals been finished? - you may just have open cavities. Mine had this and no backs to the sash boxes! Also, when thinking about electrician/services don't forget to think about e.g. cable for satellite TV or aerial outlets, speakers, network.

Bit of planning now is well worth it

 

Very good chance the house is 9" thick without a cavity - typical Viccie (my bro's house was certainly this).

Very good advice re timber lintels - even if they are in good order, it would be wise to spray-soak them in timber preservative.

 

Y quite likely. I think cavities started about 1890. My project is 1902.

 

It depends where you live. In parts of Hampshire like Portsmouth there were a lot of cavity walled houses going up in the 1860's and onwards.

 

Bare bricks: why are we guessing cavity or no?

Many solid walls built after 1890.