Can a blocked gutter cause damp?

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Damp can enter a property in many different ways. However, the most common way is via some form of penetrating damp. This happens when a defect allows water to enter from outside. This can be made even worse in areas where excess water runs onto the property.

Blocked guttering can certainly cause this kind of problem. When your gutters are completely blocked, they are no longer removing water that is collected from the roof when it rains. Instead, the water builds up in the guttering, causing them to overflow.

Gutters are designed to collect run off water and channel it into downpipes. These pipes allow the water to run directly into the houses drains. The process can divert huge amounts of water away from a property’s walls, windows, and door openings.

When large amounts of water run onto a property from overflowing gutters, this can significantly increase the chance of water entering the property, via some form of penetrating damp.

can a blocked gutter cause damp

What damage can blocked gutters cause

Overflowing gutters can cause several issues, some of the most common include:

  • Damage to facias and soffits.
  • Allowing damp to penetrate roof timbers. Long term this can lead to damp, mould, and rot, which could cause structural issues.
  • Water running into window and door openings. Any damaged or old sealant could allow water to penetrate.
  • Increased wear of brickwork and pointing. This can allow water to penetrate through the masonry and can even create new defects over time.
  • Water penetrating behind render and pebbledash. This can cause multiple problems, including excess damage to the render and further penetrating damp underneath.

Most issues will develop over time, and this is why you should fix blocked gutters as soon as you recognise the problem.

Gutter cleaning services are not that expensive and could save you a significant amount of money in future damp repairs.

Click here to see average gutter cleaning costs in your area

What causes blocked gutters

Blocked gutters are extremely common, and most blockages are caused by leaves and moss. Leaves will build up over time. They are usually blown onto the properties roof, in Autumn and early winter, when leaves are falling from trees.

This can gradually build up over the years, and as time passes the leaves will deteriorate and breakdown into mush. This broken down material can be quite stodgy and hard to shift, and as it builds up, it can completely block the gutters.

Moss can also enter your guttering in a variety of ways, the spores can be carried by the wind, insects, and birds. Once this finds its way into your gutters, even a small amount of moss can spread and grow into a significant sized plant.

Moss reproduces asexually. Therefore, all it needs to grow, is water and sunlight, which your gutters will provide in abundance. It is also extremely resilient, and even though it may appear to dry up and nearly disappear in summer. As soon as the wetter weather returns, the moss will start to absorb moisture and grow again.

Can blocked downpipes cause issues like damp

Blocked downpipes can be less obvious if the blockage is hidden inside the pipe. However, the result will be the same. In some cases, it can even be worse than a blocked gutter. This is because a blocked down pipe will back up with water and could potentially fill the entire gutter above it.

If a downpipe does block and your gutter fills with water, it will often start to overflow across the entire length of your guttering.

Regardless of whether its your downpipe or gutters that are blocked, or maybe even both. The outcome and potential for damp will be much the same and this is a problem that you should fix sooner than later.

How to clean your gutters

The good news is cleaning gutters is relatively simple. If you have a good head for heights, you can access the guttering with a ladder and manually scrape out excess leaves and moss.

To completely remove any remaining moss and avoid it returning, you can also spray the cleaned gutters with a moss killer. This will destroy any trace and prevent the moss from regrowing.

Downpipes can be slightly more complicated. However, most blockages will be at, or near the top. Once you have cleaned out any blockages at the top of the pipe, you can also run a hose pipe down the pipe to resolve any internal blockages.

You should use a naked hose pipe for this, with no fittings on the end. This will allow your hosepipe to easily travel through the downpipe. You can send the hose as far as possible, and this will push any blockages out of the way. Then follow this by hosing the downpipe with water to make sure it is flowing nice and clean.

Get a professional to clean your gutters

If you’re not keen on heights and don’t want to do the work yourself, hiring a professional gutter cleaning company is your best bet. This is usually a very affordable service (between £50 – £100 for a terrace or average sized semidetached house), and the professionals will have all the kit needed to do a top notch job.

Also, you can usually get a really good bargain on gutter cleaning, by comparing local quotes. The best way to do this is via an online trade comparison site. These sites can often get you really good discounts, and you can read past customer reviews, so you know the person you hire is up to the job.

To compare local gutter cleaning quotes in your area, Click Here


As you can see, blocked gutters can cause several problems with damp. If blocked gutters are left unattended for long periods, the damage they could potentially cause, will far outweigh the cost of having them professionally cleaned.

Because of this, you should aim to keep your guttering and downpipes in good condition. This includes free from blockage and any other damage and leaks that may occur.

It is very cheap to keep your gutters in good shape, and it is recommended that you give them a clean once per year.