Tips for Preventing Penetrating Damp

Many areas of the UK are recovering from six weeks of severe weather which has resulted in thousands of properties being left with damp problems and their owners looking for tips for preventing penetrating damp. Heavy and prolonged rainfall accompanied by high tides and storm force winds have caused misery to house-owners across the country as leaking gutters, driving rain and floods have combined to let water find a way inside homes in an area extending from London and Kent in the East to Somerset, Cornwall and Wales in the West.

The number of cases of water and dampness seeping through walls has sharply risen recently in correlation with the extreme weather; this problem is particularly bad in old or period solid-walled properties, allowing water to soak directly through bricks and mortar and into plaster until this too becomes saturated. Those living in cavity-walled housing have seen the ruin of blown fibre cavity insulation, which has become saturated as water is transferred towards the inner leaf wall.

As the term suggests, penetrating damp occurs when water penetrates to the inside via porous or cracked masonry walls. The problem is first noticed by a darkening of the walls as they absorb water which, if left unchecked, will eventually saturate the wall. During the damp stages, the masonry becomes vulnerable to damage and also provides the ideal breeding-ground for colonies of unsightly and unhealthy mould.

The prospect of penetrating damp in walls has three typical causes, all of which are aggravated by the extreme weather that was recently experienced across much of the UK; these causes include leaking gutters, flood water and even rain being driven against walls by high winds. All of these problems can be swiftly remedied with the use of professional-quality Twistfix products.

1 - Damp caused by Leaking Gutters.

As the first line of defence against the rain, gutters should always be adequately maintained to ensure water can be quickly removed from the roof of a property. Fully exposed to the air, gutters quickly become blocked with natural debris, causing water to overflow onto masonry walls. The Hedgehog Gutter Guard System, with its durable stainless steel spine surrounded by a densely-wound circlet of strong polypropylene bristles, can be installed in minutes and resolves the problem of blocked gutters completely.

2 - Penetrating Damp caused by Driving Rain.

Any masonry surface that is exposed to the elements must be sufficiently protected from them.  Bricks, blocks and mortar are porous and, under certain driving rain conditions, can soak up moisture from prolonged exposure to heavy rainfall; resulting in transmission of moisture from the outside of a solid wall to the internal decorations. With a cavity wall there can be an increased risk of rain penetration if a cavity is fully filled with insulation. rain-water can penetrate the outer leaf of brickwork leading to wetting of the cavity insulation, a reduced thermal performance and damage to internal finishes.  Twistfix supplies a range of masonry water repellents that stop driving rain in its tracks. Water repellent silicone formulations are quick and easy to apply to brick and stone walls; they soak into the masonry to leave a hidden protective layer that prevents absorption of wind-driven rain.

3 - Saturated Walls due to Floods.

When flood water rests against a wall the dampness doesn't take long to saturate the masonry; so what can be done to prevent it? For decades builders have been applying dense cement renders to the outside of vulnerable buildings to keep the dampness out.  But as renders age and sometimes crack the water finds it's way in, where it then becomes trapped behind the 'waterproof' render. Over the last few years silicone cream technology has been developed to provide a better way to stop damp penetrating through walls in times of flood. Damp Seal masonry water repellent provides incredibly effective protection as the powerful thixotropic silicone cream penetrating deeply into masonry pores to give a vapour-permeable coat.  That is it dramatically suppresses the capillary process to stop water but allow the escape of water vapour. The cream is powerful enough to equate to four standard water-repellent treatments and is incredibly popular amongst our network of registered contractors.

Top Tips for Preventing Penetrating Damp

  • Check roof coverings and gutters, fixing leaks as soon as they start.
  • Ensure window and door frames are sealed and are water tight
  • Repair cracks in brickwork and ensure pointing is sound
  • Apply water repellent facade treatment to exposed brick or stone walls
  • Use cavity drain membranes to form a physical barrier between damp masonry and internal finishes

For more information on the Twistfix range of practical solutions to the range of damp issues caused by the recent heavy rainfall and floods in the UK, please call our expert team on 0845 123 6006 or email

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