So, you’ve decided to embark on your first self-build project and are probably feeling a little daunted about where to start. With so many materials to choose from, how can you possibly select which one is most suitable for your project?
If you are completely new to construction, it may be wise to enlist the help of a small builder – a popular option for those who would like to be involved with the construction of the property but are feeling a little worried they lack the technical skills and expertise to complete the build on their own. It is worth speaking to a number of local firms to find out what they use; bearing in mind the material you use should be one both parties are happy with.
For many self-builders, ease of use is the main characteristic to look for. This makes masonry – one of the oldest and most enduring methods of construction – an easy choice. There are many different types of blocks available and the choice can sometimes feel overwhelming. We recommend looking for a block that is lightweight and easy to lay and manipulate on site. Blocks which can be cut to size on site without the need to purchase any additional (and often expensive) equipment are ideal for self-build jobs.
The thermal performance of building materials is important to consider – not just to save money on fuel bills once the build is complete, but in order to ensure your project is fully compliant with the latest Building Regulations. It is important to check the maximum permitted U-values and ensure the materials you are planning on using will meet these requirements. Using a recognised modern method of construction (MMC) is an easy way to fulfil these criteria and there are many masonry options available which offer both exceptional thermal performance and ease of use.
Most heat is lost through the home at junctions between walls or where walls meet other elements such as windows, doors, ceilings and even floors. This process is known as thermal bridging and due to increasingly strict legislation, areas of a property which might have previously been considered insignificant (such as internally part walls) can now be a major cause of thermal inefficiency.
Part L of the latest Building Regulations (Conservation of Fuel and Power) state: "The building fabric should be constructed so that there are no reasonably avoidable thermal bridges in the insulation layers caused by gaps within the various elements, at the joints between elements and at the edges of elements such as those around window and door openings". This means that preventing thermal bridging must be one of your top priorities when choosing which materials to specify in your next self-build project.
Although thermal bridging can be identified in completed buildings with the use of thermal image cameras, it is often very difficult to rectify – especially if the issue is a recurring one. Therefore, it is of vital importance to eliminate these issues right from the outset to prevent any costly remedial works later down the line.
Sound insulation is another factor to consider, especially if you don’t have the luxury of acres of fields for neighbours. When it comes to sound, choosing the right material at the outset can make all the difference. There can be huge variations in the resistance to the passage of sound and changing the specification of just one material can have a significant impact in the overall building performance.
Due to the number and complexity of potential design solutions, getting sound insulation right can be one of the most difficult parts of any self-build project. That is why we would recommend making use of the Robust Details scheme – launched in 2004 in response to the house-building industry’s call for an alternative to pre-completion sound testing in order to meet Part E of the Building Regulations.
For a small fee (£33 + VAT per dwelling), any new development can be registered with the Robust Details scheme. Users can then compare the sound insulation properties of a range of solutions and select the most appropriate for their project, thus taking the hassle and worry out of pre-completion sound testing (an approach which can quickly mean unexpected costs should any part of the design solution fail). Choosing Robust Details means you can be confident the materials you have chosen to specify will be fully compliant with Building Regulations – since the scheme was launched, over 98% of properties tested met or exceeded the legal sound performance requirements.
Finally, the performance of building materials under different weather conditions should be a key consideration when starting a self-build project. The UK’s damp climate can create numerous challenges for materials – especially during the cold winter months when freeze-thaw cycles can lead to water entering brick, concrete or natural stone in a process known as spalling. Spalling causes the surface material to peel, pop out or flake off; however, in more serious cases, can lead to crumbling of a structure.
Sulphate attack is also something to be aware of and occurs in much the same way as spalling. Sulphates can be present in the soil surrounding a building or in seawater so it is worth assessing the existing environment of your plot before commencing construction.
Having this information to hand will help you make a more informed choice when assessing the suitability of materials for your self-build project. Checking both the freeze-thaw durability and sulphate resistance of any material you are considering using by looking at both manufacturer guarantees and independent testing to verify the material’s performance will really pay off – after all, the goal of many self-builders is to construct a property that will last for not just one generation but several.