Condensation problems are never a good sign for your roof space. Managing condensation risks is incredibly important to maintain the long-term integrity of your flat roof structure. Do you worry that condensation might cause significant damage and unseen decay to your flat roof construction? Read our guide to discover the top roof condensation solutions for 2022.
What Causes Roof Condensation?
Condensation problems don’t spring out of nowhere. However, without careful maintenance, you might not notice condensation harming your roof structure. So, what causes condensation? To understand how to prevent or fix the problem, we must explain what causes roof condensation.
When the outside air changes temperature – hot air meets cold air – the air particles cannot hold suspended water molecules. Therefore, water droplets form on surfaces. You’ll recognise a misted-up window when you have many people in a warm car on a cold day; without proper ventilation, condensation forms.
The average household might generate an estimated 15 litres of water vapour daily. Just think how much damage 15 litres of water could do to your property. Throughout the day, warm air (containing water vapour) within your home rises towards the roof. If you have adequate ventilation, the air and water will escape.
However, if there is no clear way for the moist air to leave the property, it will cause condensation problems in your roof space.
Why Is Condensation Bad?
So, what’s the problem with moisture in the roof cavity? As with roof leaks, water vapour is never a good sign. Moist surfaces encourage mould and mildew – which cause decay and rot and are bad for your health. Do you want to breathe in stale, mouldy air? It’s particularly hazardous for those with respiratory problems.
The real issue with condensation is that it results in unseen decay. Over time, your roof structure will become vulnerable, and you won’t notice the damage until it’s too late. You might need extensive repairs and face a costly bill by this time.
How to Prevent Condensation
Condensation is difficult to reverse, especially if left unnoticed. The best strategy is to prevent it before it can cause any harm. Ventilation, insulation and behavioural practices can help prevent condensation. For instance, try to avoid drying clothes inside.
3 Flat Roof Condensation Solutions
Fortunately, there are several solutions to prevent and fix condensation damage. Condensation is a natural process – but you don’t need to let it destroy your structural roof deck. Here are the top three solutions for 2022.
1. Cold Roof Decks
There are two types of flat roof construction to help reduce condensation risk. The cold roof deck solution involves placing thermal insulation above or below the structural roof deck or waterproof layer. When placed below the structural deck, you need ventilation under the deck.
Cold deck construction is the most popular approach but the least thermally efficient. If you live in the more humid, tropical Australian climates, you’ll find it causes particular problems. Therefore, many builders prefer warm deck solutions instead.
2. Warm Roof Decks
On the other hand, a warm deck construction uses thermal insulation above the structural deck and waterproofing layer. You don’t need any additional ventilation.
It’s a more modern approach with greater efficiency and practicalities. However, not all buildings can use this design, particularly cramped roof spaces in built-up areas. That said, most building regulations recommend warm roof decks where possible.
Warm decks include a vapour barrier or vapour-control layer (VCL) above the structural deck. This stops moisture and moist air from entering the roof space, preventing condensation.
As long as you have a properly installed flat roof with suitable deck construction, you should have few condensation problems. Warm deck constructions are better but not always possible.
The final solution is to improve your roof space ventilation. All properties should have adequate ventilation for a multitude of reasons.
Pitched roof structures are better equipped with ventilation – for instance, they can use passive ventilation techniques that ensure the property has healthy air all day, every day. However, flat roofs are not as easy to ventilate as pitched roofs.
Why Is Ventilation Important?
Building regulations require minimum ventilated air layers beneath the deck structure to protect the roof space from temperature variations. Moisture build-up is not just costly. It might cause significant damage and a potentially hazardous roof structure if left untouched. Here are a few reasons to ensure your flat roof has adequate ventilation.
- Fresh and healthy indoor air – Encouraging air movement prevents stale air from sitting around the home.
- Air regulation – There is such a thing as too much fresh air. It can lead to costly energy bills as you try to maintain even, comfortable temperatures.
- Stop condensation – Excess water vapour can cause severe damage to your property.
Why Are Flat Roofs Hard to Ventilate?
The problem with flat and low-sloping roofs is that there is no chimney effect – where warm air passively moves out of openings in the roof space. Therefore, builders must install mechanical vents in the roof space – such as soffits – that drive air out of the property.
Flat Roof Condensation Solutions
While flat roofs are difficult to protect from condensation, it’s not impossible. Cold roof decks are the most popular choice. However, a warm roof deck is a better and more efficient flat roof condensation solution if possible. Ensure you adequately protect your flat roof structure from condensation to prevent severe damage, unseen decay, and costly repairs.