Damp Walls

Damp Walls In Your Home


I posted on my blog, in November last year, about damp walls that arise as a result not having gutters on your home to control the flow of rainwater off your roof.

On Saturday I inspected a four-year-old property that had a one tile overhang on the roof, no gutters but had paving surrounding the house.

However, the external walls of the house were in a desperate state because of the three most destructive mistakes architects, developers, builders and homeowners make!

As a result, I’m going to repeat part of the issues mentioned in my blog again!

Damp walls caused by no gutters

Gutters collect the rainwater runoff from the roof, discharging it into downpipes which conveys the rainwater away from the house in a controlled manner. In addition, they also protect the timber roof structure at the eaves of the house. Furthermore, gutters protect the exterior walls, windows and doors of the house and its foundation from damp and potential damage.

damp walls

The splashing up against the walls was the most serious cause of the penetrating damp on the walls of the house. Moreover, the crazing cracking (spiderweb-like fine cracking) in the plasterwork was the main indicator of the penetrating damp caused splashing up of rainwater. No cracking was observed higher up on the walls.

Even if your house has a reduced overhang at the eaves, gutters will still provide the required protection against heavy rain and wind storms your house may be subjected to.

Insufficient roof overhang at the eaves

Roofs with no gutters which have a two-tile overhang (600mm in the case of a metal roof) or less will allow water to pour from the roof close to the walls, windows and doors and the foundation.

damp walls

The house in question had a one-tile overhang which, in combination with the lack of gutters, caused the following:

  1. Rains had removed the joints between the paving allowing the rainwater to pool close to the house’s foundations.
  2. Stormwater pooling in the joints close to the foundation was absorbed by the ground and may cause extensive damage over time.
  3. Stormwater pouring off the roof splashed up against the walls of the house. This caused moisture intrusion into the walls and damage to painted and plastered finishes. This caused a phenomenon called penetrating damp!
  4. Windows and doors were more exposed to windblown stormwater pouring over the edge of the roof resulting in the increased moisture intrusion into the home through cracks in the window sills and at the frames of the windows.
  5. The additional volume of stormwater discharged from valleys in the roof was also problematic causing additional damage to the plasterwork and paintwork.
damp walls

However, it is not a practical solution to increase the roof overhang on the house. Therefore, you should regularly seal all cracks in walls, window sills and around window frames. Ultimately, gutters still remain the best solution to protect your home!

Insufficient allowance between the finished ground level and the floor level of the house.

The Buiding Regulations require a minimum distance of 150 mm between the exterior finished ground level and floor level of the house. Moreover, this includes the building in of a horizontal layer of DPC layer (damp proof course) at floor level to prevent the wicking up of groundwater above floor level through the masonry walls.

rising damp

As you will see in the photographs, rising damp is usually confined to lower parts of the walls, not rising much more than 1 metre up the wall.

High exterior paving levels was the cause of water penetrating the wall above the DPC and manifesting in rising damp together with penetrating damp on this property.

Therefore, the lowering of the exterior ground and paving level would be the practical remedy.

Regular maintenance to prevent damp walls

It is important to check and maintain the outside of your home regularly for damage caused by moisture. Particularly, all cracks on the outside of your house will allow moisture into the wall structure.

Furthermore, areas damaged by damp should not be redecorated until the cause of the damp has been identified and repaired.

If you do have gutters, you will need to maintain them and keep them free of leaves and debris. Therefore, create a 6 monthly maintenance schedule for cleaning your gutters and checking walls and window sills for cracks.

Alternatively, you should have a maintenance inspection which is ideal for newer homeowners and busy homeowners who don’t have the experience or the time to check and maintain their homes themselves. Lastly, this type of inspection is also especially suited for older or physically handicapped homeowners who, nevertheless, want to keep their homes in tiptop condition.

It’s the home’s equivalent of a medical checkup!


Inspected Once, Inspected Right!®


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