Designing for airtightness  

Designing for airtightness is a key area that many architecture and contractors keep in mind when creating something unique for creative. It is essential to keep up with the building regulations, as it is a main feature to pass to make buildings more efficient.   

The air barrier of a building will include a set of fundamentals that comply with each other to offer airtightness. These should be looked at throughout the design process. When looking at this, we can understand how design functions can be viewed and achieved for airtightness, and can also see how it can work and problems allies. Materials analysed for airtightness.  

Design and producing construction ideas is a developer dream, but you have to understand the air barrier line around a build, this would-be roof, walls and floors. You could say it is similar to a thermal envelope, which provides insulation for the borderline.  

It's common that internal air barriers are used in the UK, but these do have many penetrations which require parts. The barrier will need an additional coat to be laid on to certain areas, but for those areas that are not needed, it will be acceptable. An example of this (OSB) is known as oriented stand board. This material is airtight, ensure you seal correctly at the joints of the boards. 

Like most materials, there are always different variations. This means you can find a better airtight product of an OSB. That is why it is important to add or remove details and products used for a build, also for existing, if you want to add or remove to create better airtightness. When looking for specific components to construct when it comes to airtightness or even sound insulation, it will provide you with the information that the item is used for more air tight or its sounder proof.  

Concrete is a material with high elements that blocks air paths. There's no need to add further layers around this material. Masonry can also be advanced into an added airtight material. All you need is a thin layer of mortar. 

Buildings are complicated designs that provide many structural links, which are designed for walls, floor and roof. Where these complex junctions are is where most of the air would travel through. So, it is ideal to get these details cautiously done, so that you can achieve good airtightness. The main idea is to ensure that there are no gaps or cracks in any building fabric where air can penetrate and flow through.   

These are a list of air paths:  

• •  Waste pipes

• •  Soil pipes

• •  Ventilation ducts

• •  Windows and doors

• •  Air condition unit and heating system

• •  Chimneys and flues

• •  Wood burner

• •  Sockets

• •  Lights

• •  Security cameras

• •  Satellite dish 

Designing a healthy building  

Designers are always aware of keeping the build air tight, because they always look at building regulations when designing. An internal air barrier will stop warm internal air from entering the build, cooling down and increasing the risk of condensation. Don’t get this confused, for vapour control, this stops vapour diffusion. Vapour diffusion and moisture risks are different design sections, but it can link in with airtightness. Best part is to fix an air barrier on the warm side of the insulation, this would be between the insulation and structure of the frame.  

Testing the design  

If possible, the airtightness layer within all elements, such as walls, roof and floor. These should be tested while it is still reachable, so corrective sealing works can be carried out if needed. If it is difficult to like bigger developments, the efficiency of the airtightness can be checked in stages by sampling and testing small areas of the build. If you want to ensure the build is airtight, you can do a pre-test just before the final stage to identify leakages. This can help solve issues before it gets worse once everything is fitted.  

Testing of multiple builds within one property will be intricate if the air barrier has been designed around the entire building. An example of this would be entering flats through an external or internal stairwell, or maybe an access balcony or an internal corridor. Flats can only be tested separately, then the airtightness layer should be designed within each flat. 

• •  For a long duration of the roof, it might be easier for the builder to install an airtight board rather than applying a membrane 

• •  Contractors are aware that with a plaster finish on traditional brick and block walls, this would be the barrier. You can use parge coat or     paint specific for airtightness, and use that for sealing. 

• •  Construction with timber frame is probably expected to use an internal racking board. This material can be produced to a better airtight     fabric. 

• •  For a retrofit procedure, an external wall insulation can have an air barrier put in before an insulation layer 

•  Simple design compared to complex  

It's always amazing to see unique concepts of building, but if you want to ensure you can have an airtight home, then it is ideally to keep it simple. Structures like junctions, balconies, dormers and other features struggle with airtightness. These are features that can be applied to the building design, like balconies, because if they are externally supported, they won’t be too airtight.  

• •  Reducing joints

• If you are designing, then try to limit the number of junctions within a build. An example of this would be dormer windows. This feature will have loads of joints applied to the roof, which will have to be then airtight. Also, with many joints, it will be difficult to insulate. 

• •  Air barrier and services 

• A service void can be used to ensure that spacing through walls and other elements is adequate sealing.  

•  

• •  Products created for airtightness

• If you weren’t aware, there are products that are supplied and created just for airtightness. There are still products being developed for specific fabric.  

What can go wrong?  

Majority of the time for incomplete or poor design for an airtightness of a build will come to a contractor not understanding or knowing the procedure around this, whilst being able to inform other workmen, so not having great management skills or just not knowing site culture. This would usually delay projects, cost extra money, and fail the airtightness test. It is important to have a designer and contractor on the same page, knowing all the key details involved with a complex build and all the areas that need to be airtight. When you look into the fundamentals of an air pressure test, it’s not that difficult to obey and get the solutions done before an engineer comes to test.   

Overview  

When looking at everything, it comes down to understanding and communication, and also having the right people involved. You want to understand the basic fundamentals of design and what materials are used to create a build. What materials can be used for a better air tightness score, or even what elements to look at to solve the airtightness problems that happen within a build.  If you have any concerns or just want to find out, don’t worry, contact us at ATSPACE and we will be happy to help. We also have links and videos that do in-depth about air pressure testing to sound testing, and also different types of ventilations.