Wet, windy weather highlights damp proofing issues

It seems we will be swept into May with wet, wild and windy weather. The forecast is for south westerly storms with gusts to over 50 mph at times in parts of southern England and south Wales, and to 60 mph in some exposed coastal sites.

It may take a blast of wet and windy weather to highlight some of the common defects in properties that can lead to internal dampness. Here are some problems that could lead to signs of damp:

• Leaking gutters & rainwater pipes – If gutters and rainwater pipes become blocked with debris such as leaves and detritus the constant over spilling of rainwater can cause damp ingress, particularly in solid walls. Clean out rainwater goods and check for damage on a regular basis.

• Open chimneys & faulty flashings – Open chimneys can allow rainwater to enter into the chimney cavity and eventually permeate down through the building. Flashings are made of several types of metal (lead, copper, galvanised steel) but they can weather and if holes or cracks appear and water enters around the chimney and seep down into the roofing and eventually the ceiling. Check the integrity of flashings and chimney pots on a regular basis.

• High external ground level – If a flower bed or the general ground level is above the original damp proof course (DPC) of a property or the level of the internal ground floor, this can lead to dampness in adjacent walls. External ground levels should be kept to a minimum of 15cm below the damp proof course of a property.

• Blocked external vents – If you have suspended floors the space beneath them needs to be adequately ventilated, otherwise excess moisture can builds up. This can lead to low level dampness in walls and can eventually lead to the decay of the suspended wooden floor. Check the air bricks that ventilate these voids are not blocked, damaged or missing.

There are also other general defects that may lead to internal dampness. If the mortar course in external walls is defective or poor. If the sealant around windows and doors is defective or if stone window sills are cracked.

It’s important to have effective damp proofing. If it is damaged, absent or bridged in any way this can potentially lead to problems such as rising damp, dry rot or wet rot. Don’t wait for wet and windy weather to highlight any damp issues. If you notice stains or damp patches on interior walls, it is worth getting a professional Certificated Surveyor in Remedial Treatment (CSRT) to complete a survey of your property.