Rising Damp and How To Treat It



Here are some informative videos on how to diagnose and treat rising damp.



Video Transcript


“What is rising damp?

Rising damp is a relatively rare form of damp that affects the walls of buildings. It occurs when moisture from the ground travels up through the bricks.

What does rising damp look like?
Bubbling or flaking paint
Peeling plaster
Tide marks on your walls
White fluffy salt deposits

What are the causes of rising damp?
Rising damp is often caused by a failed or lack of an impermeable Damp Proof Course. Meaning there’s nothing to stop water travelling up through the ground into your brickwork.¬† DPC’s can also be bridged for a number of reasons including debris within the wall cavity. From soil or mud piled against the wall or when the external ground level is higher than the DPC.

Misdiagnosis of rising damp:
Rising damp is often confused with damp caused by condensation. “Samples from within the centre of the wall will not be damp if condensation is the sole cause.”

How to treat rising damp:
The most effective and economical way to treat rising damp due to a missing DPC is with damp proofing injection cream. The cream is injected into specially-positioned holes in the mortar course and creates a powerful water-repellent barrier.

Once the above has been completed, you can remove any wallpaper and plaster in order to redecorate.”




Video Transcript


“The 3 Main Types of Damp In Homes – Part 1

Rising Damp
Rising damp is the moisture that rises up from the ground in a structure when a buildings damp course has failed. This occurs in the external and internal masonry walls. There are lots of reasons the original damp course could have failed including movement of the building, alteration works to the building or even one not being installed at all. If left unchecked this can cause severe damage to the fabric of the building manifesting in damp and crumbling plaster and rotten wooden skirting boards and floors. Telltale signs of rising damp are white salts in the form of a white powdery crumbling plaster or a tide mark of damp plaster running along the wall.

We use the full dry zone rising damp treatment system. The first part of the treatment is to remove the skirting boards and to chop off the plaster to a minimum height of 1 meter or 300 millimetres above any signs of damp back to the brickwork to the affected walls.
The next stage is to insert the new damp proof course using either dry zone DPC cream or dry zone DPC rods
which will stop all future rising damp completely.
We then apply a 5 ml thick scratch coat of dry zone or dry coat salt and a resistant backing plaster. This will act as an anchoring layer so that the next coat can be better applied to for the desired straight wall finish.
Once the scratch coat has become firm we apply the plaster coat that is cut back and straightened to match the existing plaster on the walls above the treatment.

Finally we reapply the traditional pink finish plaster that is troweled smooth and blended into the existing walls to leave an excellent drywall ready for skirting boards and decoration.

Sometimes, if there is a high level of damp in the walls to be treated, we adopt a belt and braces approach
and install a dry base flex membrane to the affected areas before plastering. This forms the impervious barrier totally eliminating any damp surfacing through the new plaster as the drying process takes place. It’s applied using a drybase flex membrane bedded into a drybase flex adhesive which is then ready to take the traditional wet plastering system leaving the walls permanently dry and damp free, ready for decoration.”



Contact Damp Proofing Cape Town for a quote