Maintenance and repair of exterior walls
We are happy to pay a lot of attention to the inside of our house, but forget the outer walls. A poorly maintained exterior wall with holes, mold, loose material or crumbling joints causes moisture problems and even leaks in the house. Good maintenance is therefore necessary and with a small investment and some skill, this can be easily carried out yourself.
The usual materials for exterior walls are brick, stone or concrete. We limit our advice to the brick wall, where repair work is often easy to undertake yourself. Re-grouting a brick wall is very easy, for example.
Grouting a wall
Crumbled grout (cement) leaves water between the grout stones penetrate and cause moisture problems on the inside of the wall. Only need to grout a small part of the wall, buy a small bag of dry ready-to-use cement, the contents of which can be immediately prepared with water. For large surfaces it is cheaper to buy the components separately and mix 1 part cement with 3 to 4 parts fine sand. Add water but make the mixture soil-dry; if it is too thin it will run down the wall and cause stains.
First cut out the old grout with a chisel and sledgehammer, without damaging the bricks and clean the wall surface and the cut out joints with a stiff brush. Shortly before grouting the add moisten well with a wet brush; this means that the dry stones do not suck the water out of the mortar.
Place the mortar on a savings board, then:
- Use a small pointed trowel or joint nail to work the mortar firmly into the joints.
- First fill the butt joints (vertical), then fill the ribbon joints (horizontal).
- Remove the surplus with the side of the trowel and level all joints,
- In warm weather, spray the joints with water for a few days.
Remove water stains on exterior walls
Brick walls can show all kinds of stains. Usually they are caused by moisture, which “decomposes”. must become; firstly to remove the stains and secondly to prevent damage to the wall.
Algae, moss and fungus can be removed with a trowel or putty knife, while algae and fungus with a stiff brush. If the wall is clean, treat with a fungicide (chemical pesticide) solution. After application, rinse the wall thoroughly with water after 24 hours.
In the event of water stains, the cause must first be remedied (leaking gutter, leakage from the inside, etc.) and the wall must be dry. Then treat the wall with a covering agent (based on alum, aluminum sulphate), so that the moisture no longer penetrates the wall.
These are powdery layers that can extend over large areas. They mainly occur with new walls, usually after the wall has dried.
The powder is created because salts in the stone and mortar are sucked to the surface together with moisture. You can tackle the problem with chemical agents, but usually it is enough and also more environmentally friendly just brushing off the powder. The salt rash not with water do the dishes; this rather aggravates the matter because the salts are dissolved again and reattached elsewhere.
Dust and dirt are best washed off with a solution of water and soap powder. Scrub small dirt spots with clean water.