Interior - Cleaning Masonry Wall & Varnishing Brickwork?

[EViS]

We took the blistering (old penetrating damp problem) plaster & render down from a small wall in our home. The brickwork looks very nice & we'd like to make a feature of this...

What's the best way to clean all the remaining covering of cement/render on the brickwork? Simply alot of elbow grease and sanding/wire brushing? Or is there some sort of chemical that may help with this?

Next, what sort of varnish is usually applied to interior brickwork to preserve it and bring out all the colours?

 

[tryingnottobeafool]

a natural finish is best and help the wall to breathe

elbow grease and possibly re-pointing

 

[Symptoms]

EviS - get some mortar cleaner (sometimes called brick cleaner), comes in 5L & available from builders merchant. It's an acid specifically designed for cleaning off mortar residue from brickwork. Care needs to be taken when working indoors - address only a small number of bricks at a time (not the whole wall) & try to avoid getting too much of the stuff on the mortar lines.

Googles, rubber gloves, old clothes on, plastic sheet on the floor, don't splash the stuff around - otherwise OK to use (really, don't be too worried).

Technique - decant some cleaner into a plastic bowl (watch out for dribbles from the can onto the floor), gently 'paint' the stuff onto the offending brick, watch it effervesce on the cement, plenty of old wet rag (an old wet towel is great) rubbed on to neutralize the acid & wipe away the cement, bricks left nice & clean. We also use this mortar cleaner for refurbishing enamel baths, ceramic basins/bog pans, etc. as it's a brill limescale remover (works on taps also, but you have to be quick with the water neutralizing).

Don't varnish the walls - it'll soak-up gallons of the stuff if very porous and/or old. If you really, really want to varnish use polyurethane, dilute the first coat with 40% white spirit, then subsequent coats neat.

 

[EViS]

Thanks for the mortar cleaner recommendation there Symptoms. We've wire brushed/sanded all the render off, however the bricks could benefit with a deeper clean yet.

a ) Is it the norm NOT to varnish brickwork then? Is varnishing not the same as applying paint onto plastered walls in therms of the walls' breatheability?

b ) Otherwise, any other way to bring all the nice colour of the brickwork out?

 

[oldbutgood]

We did our by buying a £30 sand blasting gun from Machine Mart, Dry sand from builders merchant (sharp sand not builders sand), and masks etc, and hire a 13CFM compressor for 3 days.... done and dusty.

 

[JohnD]

If your house is completely free of decoration, carpets, furniture, wallpaper, appliances, curtains and carpets from top to bottom, sand-blasting is worth a try.