Surface Condensation: Simple Guide To Understanding Its Causes & How to Prevent It

Previously, we looked at the causes of interstitial condensation and how the team at SPS Roofing can help avoid it. It is equally important to also explore the impact of surface condensation and how they can be prevented too. This article would delve into the problems of surface condensation and what preventive measures your roofing company could take to ensure your roof is long lasting.

What causes surface condensation?

Surface condensation takes place when the air cannot hold any more moisture and droplets of water begin to form on surfaces which include walls, ceilings and even under roofing underlays in cold lofts. A sudden change in air temperature can allow moisture to seep through to the surfaces which eventually causes condensation.

The problems can be aggravated during cold climates when people are keen to keep warmth in and cold out by limiting air exchange in the home.

Does it occur in roof spaces?

In short, yes it’s possible. Condensation occurs in roof spaces when there is inadequate roofing ventilation or there is either too much warm air circulating upwards from living spaces. Given that older homes had less accurate building methods, it helped moisture to easily escape and therefore had better ventilation. 

However, more modern methods of building are designed to have better thermal insulation in a bid to reduce energy consumption. As such, one of the side effects of this is to trap the moisture, thereby increasing the chances of surface condensation on roofing surfaces.

When does it become a problem?

Surface condensation usually does not pose imminent threat to your roofing structure. Due to extremely cold weather, residents tend to limit air exchange in the home which can lead to condensation that usually dissipates from the underlay with no harm done. 

Slowly but surely, condensation could build up allowing other roof elements such as rafters and insulation to become wet, causing water staining on the ceiling or structural damage to the roof.

What are the solutions to surface condensation?

One of the most common ways to solve the problem of surface condensation is to ensure there is plenty of ventilation. There are many roof ventilation products on the market, including eaves, concealed tile, ridge and top abutment ventilators

Our expert roofing team at SPS Roofing can advise you on the best type of products and also place them in a manner that optimises the ventilation flow. For instance, cross-flow ventilation can be improved by installing ventilators just above the horizontal insulation at either side of the roof.

Additionally, good external air flow is also key to ensure ventilation works well. Our roofing experts would factor them in during the roofing design process.

Choosing the right type of roofing underlay

It is also important to choose a roofing underlay that would help avoid a build up of condensation. If installed correctly, they can be a key step towards eliminating any moisture buildup.

When installing a roofing underlay, it is important that you tape down laps to prevent them flapping in windy conditions. This is one of the common mistakes and one that you should try to avoid.

Below are some of the different types of roofing underlays can help prevent surface condensation:

  • Non-breathable underlay: These membranes act as an extremely effective secondary barrier and if used with the right ventilation system, they can be useful in preventing condensation.
  • Vapour permeable underlay: These allow water vapour to escape whilst providing a barrier to wind and rain, letting moisture out without letting it in. Once again, they have to be used in conjunction with a good ventilation system.
  • Air permeable underlay: Though this is a more expensive option, it provides an extra level of performance if a belt and braces approach is needed. However, this won’t really be necessary if you have an adequate ventilation system in place.

How to prevent surface condensation?

Surface condensation is something that is usually not given immediate care or attention that it needs by most homeowners. This is because it does not cause an immediate threat to the structure but can be a costly repair if ignored. 

Unfortunately, there is no quick fix, cost-cutting solution that exists. With the combination of a suitable ventilation system and good quality underlay, your roofers at SPS Roofing can help solve the problem of surface condensation.

Need help with fixing surface condensation issues?

Should you need any help or more information on matters relating to surface condensation, please do not hesitate to contact SPS Roofing Ltd or give our team a call directly on 01392 549740. Through our roof repair servicing division, we can arrange our team to inspect and suggest the right course of action.

For further reading or information, Property Care has published a PDF that provides a detailed guide on condensation and how to prevent it.

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