Damp Walls In Your Home
I posted on my blog, in November last year, about damp walls that arise as a result of 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. There were no gutters, but the house had paving surrounding it.
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 some of the issues mentioned in my blog!
Damp walls caused by the lack of gutters
Gutters collect rainwater runoff from the roof through downpipes. These convey rainwater onto concrete rainwater channels 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 house’s exterior walls, windows, and doors. They also protect the foundation from damp and potential damage.
The splashing against the walls was the most serious cause of the penetrating damp on the house walls. Moreover, the crazing cracking (spiderweb-like fine cracking) in the plasterwork was the main indicator of the penetrating damp caused by this splashing up of rainwater. Cracking was not 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.
Insufficient roof overhang at the eaves
Roofs with no gutters and a two-tile overhang (600mm for a metal roof) or less will allow water to fall off the roof close to the walls, windows, doors, and the foundation.
The house in question had a one-tile overhang, which, in combination with the lack of gutters, caused the following:
- The rain had removed the joints between the paving, allowing the rainwater to pool close to the house’s foundations.
- Stormwater pooling in the joints was absorbed into the ground close to the foundations. This may cause extensive damage over time.
- 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!
- Windows and doors were more exposed to windblown stormwater pouring over the edge of the roof. This resulted in increased moisture intrusion into the home through cracks between the window sills and window frames.
- The additional stormwater volume discharged from roof valleys was also problematic. It caused additional damage to the plasterwork and paintwork.
However, it is not practical to increase the roof overhang. Therefore, you should regularly seal all cracks in walls, window sills, and around window frames. Ultimately, gutters remain the best solution to protect your home!
Insufficient allowance between the finished ground level and the floor level of the house.
The Building Regulations require a minimum distance of 150 mm between the finished ground level and the house’s floor level. Moreover, this includes a horizontal DPC layer (damp-proof course) at floor level. This prevents the wicking up of groundwater above floor level through the masonry walls.
Rising damp is usually confined to the lower parts of the walls. It does not rise much more than 1 meter up the wall.
High exterior paving levels caused water to penetrate the wall above the DPC. This manifested as rising damp together with penetrating damp on this property.
Therefore, lowering the exterior ground and paving level would be the practical remedy.
Regular maintenance to prevent damp walls
It is important to regularly check and repair the moisture damage on the house’s walls. 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 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-month maintenance schedule for gutter cleaning and checking walls and window sills for cracks.
Alternatively, you should have a maintenance inspection. This 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 suited for older or physically challenged homeowners who 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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