With the energy efficiency requirements of new builds seemingly on an endless rise and homeowners constantly looking at ways to improve insulation in their existing property, ventilation can sometimes fall by the wayside, especially when it comes to modern home improvements.
While there is absolutely nothing wrong with upgrading from double glazing to triple glazing or filling wall cavities with insulation, when these changes are made without thought for ventilation, problems can arise, chiefly condensation.
Generally speaking, the more insulation a building has in place, the less pockets for water vapour to escape a building from.
This warm moist air built up from running hot water in bathrooms and kitchens, but also from simply speaking, breathing and eating, naturally rises up through a building until it reaches the loft space (if there is one) where it can condensate if adequate ventilation is not in place.
While it is not recommended to be used in isolation, fitting a breather membrane, such as the APEX silver breathable membrane, under the tiles and supporting battens can give water vapour an easily navigable escape route.
Using breather roof membrane alongside a high/low ventilation system in the roof space via tile vents or a traditional eaves/ridge combination will create a fresh circulation of air that will greatly reduce the chances of condensation.
The dangers of condensation are well known by now. Not only can the mould and damp by-product be hugely unsightly when spotting on the ceiling below, it can also cause respiratory problems for anybody living or working in the building.
Installing APEX or a similar breathable membrane in place as part of a wider loft ventilation system can be just as important as insulating your home, especially in existing properties.
What Exactly is Breathable Membrane?
Breather membrane, also called low resistance membrane, is a roofing underlay that sits under the roof tiles. Along with air permeability, the primary functions of breather membrane are to stop water entering the roof structure and preventing wind uplift.
The low resistance classification given to breather membrane is done so by British Standards and relates to the membrane’s water vapour resistance.
In principle, the lower the water vapour resistance, the greater the membrane’s ability to lower the risk of condensation.
Non-breather membrane, which is still widely used in roof structures and was for long the roofing underlay of choice, does not allow water vapour to pass through it and is therefore know as a high resistance membrane.
Both breather roof membrane and non-breathable membrane are lightweight underlay alternatives to traditional bituminous 1F products.
The popularity of breathable roof membrane has soared in recent years as designers have realised its potential to let the more energy efficient homes of today breathe a little easier.
Non-breather membrane is still suitable for cold ventilation roof systems where other roof ventilation is already in situ. These non-permeable underlays have greater absorbency properties, soaking up any water vapour rather than transfering it.
Whether it be breathable membrane or high resistance membrane, all effort should be made to improve fresh air flow in the roof space to reduce the chances of condensation. Untouched Buildings with little ventilation will naturally not require as much, if any.
How to Spot a Good Breathable Roof Membrane
Thickness. A good breathable roof membrane should be suitability thick in order to resist tearing. For this reason, thicker membranes tend to have longer lifespans. Thicker breather membrane also tend to have superior wind resistance. Some underlays are only compliant with certain wind zones as stated in BS5534.
The best breathable membrane will be that which strikes a balance between thickness and price. Anything too cheap should send alarm bells ringing, while the more expensive underlays can sometime be unnecessary with more affordable products able to do the same job.
APEX silver breather membrane is a perfect example of an economical membrane that has good thickness, air permeability and resistance to ageing.
APEX breathable membrane is available in two sizes, both of which offer outstanding protection from wind, dust and pollution.
Get 5% on your order when you buy breather membrane alonside a RoofLITE pitched roof window, a handy saving if you are undergoing a loft conversion or refurb.
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