​Signs of and solutions for wall ventilation problems

Why is through wall ventilation required?

What are typical problems associated with through wall ventilation?

What are the signs of a through wall ventilation problem?

What types of through wall and cavity wall ventilation are available?

Which through wall ventilation methods are possible?

Which through wall and cavity wall ventilation products do Manthorpe supply?

How can I get hold of Manthorpe through wall and cavity wall ventilation products?

Why is through wall ventilation required?

Through wall ventilation in buildings is required for a variety of reasons across a range of situations. It can be achieved by a variety of means such as air bricks, pipes and grilles and core vents. As living spaces have recently become more energy-efficient and often more insulated, the need to ensure that sufficient ventilation is provided in all manner of spaces has become more important, in order to prevent the build-up of stagnant air, harmful gases and Condensation.

These spaces need to be energy efficient as well as needing to ‘breathe’. The correct choice of through wall ventilation strikes the balance between these potentially conflicting requirements. Some construction methods that might restrict the flow of air within a space are:

• Improved wall and floor insulation materials and methods
• Improvements in material properties and manufacturing methods for door and windows along with an increase in double and triple-glazing’s popularity
• Improved construction and building practice to prevent unintentional gaps within structures

Whilst these improvements are welcome, their impact on other aspects of the building design must be borne in mind.

Approved Document F of the Building Regulations outlines the requirements for the provision of through wall ventilation. This can be for any one or more of the following reasons:

• Provision of outside air for breathing
• Dilution and removal of airborne pollutants, including odours
• Control of excess humidity (arising from water vapour in indoor air)

Building designers will specify the amount of ventilation required and the most suitable method according to the regulations and using calculations relating to the volume of the space and its use.

What are typical problems associated with through wall ventilation?

Through wall ventilation can be compromised in a number of ways, sometimes purposefully to prevent drafts but often inadvertently such as by the placement of furniture, the alteration of internal structures such as walls or the blocking of outside ventilation grills by vegetation or additional extensions or buildings. If these blockages remain unaddressed, stagnant air can build up in a living space and fresh air cannot be exchanged from the outside. This can result in poor health due to low quality air and possible mould growth caused by trapped condensation, which in turn can cause respiratory issues and sometimes expensive damage to the property if left unchecked.

It’s therefore vital that any modifications to a property should consider possible effects on living space ventilation.

What are the signs of a through wall ventilation problem?

One of the first and most obvious signs of poor ventilation in a room or a property is mould growth. Well-known sites for mould are bathrooms and kitchens which by their nature contain damp and need excellent ventilation but less obvious locations are window perimeters where mould results from condensation build-up due to cold bridging.

What types of through wall and cavity wall ventilation are available?

In modern housing and new construction, the correct amount of ventilation will have been calculated and specified by the building designers from the outset. In older buildings, retro-fitting might be required in order to accommodate changes and adhere to Building Regulations, in particular Approved Document F.

An air brick will provide cavity wall ventilation as well as underfloor void ventilation. A controlled geometric free area allowing building designers to accurately calculate how many are required for ventilating a specific area of the build.

For fitting wall vents retrospectively in particular situations such as the venting of an interior space with a gas appliance, where in accordance with BS5440, a 5” core drill vent can be used. However, these same vents can be used for general living space ventilation needs as well, especially in areas with inadequate ventilation.

Weep vents are used for cavity wall ventilation purposes, for example, in a timber frame construction. As well as facilitating airflow and circulation in, out and throughout the cavity, the weep vent also drains excess moisture from the cavity, further assisting in the prevention of damp build-up and harmful mould growth. Whilst weep vents are usually installed at the time of construction, it is possible to fit them retrospectively to improve cavity wall ventilation if required.

Which wall ventilation methods are possible?

Living space ventilation systems can either be passive ventilators (making use of natural forces such as wind and convection to encourage airflow through the property) or mechanically driven ventilators such as MEV systems (Mechanical Extract Ventilation) and MVHR systems (Mechanical Ventilation with Heat Recovery). Both passive and mechanical ventilation systems usually rely on fresh air inlet and polluted air outlet products installed within the wall or roof construction of the property.

Which through wall and cavity wall ventilation products do Manthorpe supply?

Living Space Ventilation Products

• G900 / G901 Core Drill Ventilator: The Manthorpe 5” Core Drill Vent is designed predominantly for use when ventilating a gas appliance in accordance with BS5440, although can be used to supply general through-wall ventilation as well.

• Thru…air®: The Thru...air product is designed to provide a ventilation outlet/inlet using a 4/5/6inch telescopic pipe to a Manthorpe single/double/triple airbrick. Each Thru...air unit allows for an extraction terminal to be conveniently built into the brickwork, eliminating the need for retrospective core drilling. can also be used with MVHR, MEV or intermittent extraction. 

• G930 Airbrick: The G930 Combination Airbrick has been designed to provide high levels of ventilation through walls and into under floor voids when used in combination with other products within our range.

• Wall Mounted Grilles: A range of plastic and aluminium internal grill covers, offering a variety of geometric free airflows suitable for the ventilation requirements of different living spaces.

Cavity Wall Ventilation Products

• G950: The G950 Weep Vent used to ventilate cavity walls and is generally used to drain lintel trays, DPC’S and cavity trays.

• G952: The G952 Refurbishment Weep Vent is designed to provide cavity wall ventilation to existing walls to solve the problem of missing or inadequate ventilation.

How can I get hold of Manthorpe through wall ventilation products?

Manthorpe’s range of through wall ventilation products is available through a wide selection of merchants. A list of stockists is available on this site, but should you have any further questions on stockist locations, or through wall ventilation in general, please get in touch by phone, email or completing our contact form.