Damp in Basement and Cellars? What to Look Out For

Do You Have Damp in Your Basement or Cellar?

Throughout London and the Home Counties, many homes have basements or cellars which are used something like a garage – to store a few items or maybe house a boiler or a tumble dryer.  They are often considered wasted spaces that are dark, damp and cold and unsuitable for everyday purposes.  

However, if you have a vision of what it could be like or what you would like to use it for, then there are methods of damp-proofing that can be used to make your vision a reality and create valuable additional living space and your favorite room.

Moisture in basements

Whether your property has a basement, cellar or just a vault, they probably face the same problem – damp. Because they are mostly, or completely built underground, they have a far greater risk of damp than standard rooms.  

Damp problems in basements are very common but because the areas may not frequently be used, homeowners rarely think about it or what benefits they have right under their feet.  If you are considering a basement conversion then, without doubt, damp-proofing should be your priority. This should only ever be handled by an experienced damp proofing company and carried out under a long-term guarantee.

There are two main reasons why damp affects walls below ground level – lateral damp which is forced through the wall by pressure and rising-damp from upon the ground, by capillary action.  

In the winter, problems with condensation can occur and if there has been an exceptional amount of rain the water table rises and can cause flooding. Whatever the reason an experienced damp consultant should be instructed, who will recommend the most suitable solution to keep your rooms dry.

How damp occurs

The main type of damp to affect rooms below ground level is called lateral damp penetration. This is caused by ground water being forced through the wall by hydrostatic pressure. The movement of water through the wall can cause enormous damage both internally and structurally and must be controlled as a priority.

Rising-damp occurs when there is not a sound damp proof course at the base of the walls to prevent it. Damp from the ground rises through the pores of the brickwork and masonry, by capillary action and can rise to a height of approximately 1.5 meters. This also must be dealt with, as a separate item, by a qualified damp expert.

All types of damp create similar signs for homeowners to watch for in the basement.  

Large damp patches on the walls, cold to the touch. Decolourization and degrading wall plaster, rotting joinery, musty, damp smells and at the very worst, dry-rot fungus.

Basement Damp proofing

On the positive side, a damp basement doesn’t intend that your plans for additional living space are over because a damp expert such as Tapco HomeDry has several solutions that can solve the problems.  

The process starts with an assessment of exactly what is causing the damp and what method of damp proofing is the most suitable for the problem at your property.

Once the assessment has been carried out it is likely that we will recommend one of the two following options.

A Cavity Drain Membrane (CDM)

This is a high-density Polyethene, studded membrane which is installed to the walls or ceilings using special water-proof fixing plugs. A sump and pump are often installed into the floor before a damp expert installing a larger studded floor membrane. The floor is either screeded or overlaid with treated flooring. Galvanized framing is then installed before dry-lining of the membrane can be plastered directly onto.

This method of damp-proofing is not designed to block the damp but to allow it in and controlled to where we want to take it before being discharged to a place chosen by us.

Structural Damp-Proofing (Tanking)

This method of damp proofing is designed to block the movement of water through the walls.

Following a coat of waterproof rendering, slurry coats of a cementitious tanking system are applied to the walls, floors or ceilings, before further damp proof plastering being carried out.