What are Roof Battens
Timber roof battens are a crucial determiner in the structural integrity of a project, providing vital functions to strengthen, protect and maintain your roof. This guide will explore battens’ uses, their - often overlooked - significance, and some installation tips, all in hopes to ensure you select the correct batten for the job at hand!
Contents
Intro
Whether you are refurbishing an existing house or building a new one, installing roof battens, also known as roofing battens, or roofing lath, is a crucial step. Quality battens perform several essential functions in a roof structure and are a vital part of forming a secure roof, yet their value can often be overlooked. With so much riding on roof battens, specifying the correct product for the job at hand is vital, and failure to comply with the relevant standards could impact the overall life expectancy of your roof.
*** This guide has been crafted to help you to understand the uses and characteristics of roof battens. All information provided is compliant with BS 5534:2014 recommendations, which is the British Standard that sets out the requirements for roofing battens, covering everything from the type and size of timber required, to spacing and fixings. ***What are roof battens?
Roof battens are the lengths of wood that are laid between the rafters to secure the roofing felt and to accept the tiles or slates when they are fitted. They are supplied in 25x38mm and come anywhere from 3m in length, though typically 3.6m is supplied. Although battens may be hidden by the roof covering, they remain integral to the roof construction process; their job is to provide a reliable anchor for securing roof tiles, to hold the weight of these tiles, and ensure rigidity and weather-tightness of the finished roof.
Here at Builder Depot, all our battens are individually marked for full identification, highlighting size, species, grade (TB33) and treatment process. They are also pre-graded to comply with British Standards BS5534:2003+A1:2010.
What are roof battens used for?
Roof battens have many benefits to consider, including…
- Consistency in size and length
- Made from durable and treated timber, but can also be plastic to reduce the risk of decay
- Roof battens are strong and capable of carrying both ‘dead’ loads (constant factors, e.g. the weight of the tiles on the roof) and ‘live’ loads (variable factors, e.g. snow)
Staying true to their name, roof battens are used to help with roofing projects, but they do more than just provide a surface for roofing tiles. Due to their above-mentioned features, they are ideal for…
- Providing footholds for roofers
- Being a strong anchor for nails or clips
- Taking the loads imposed by slates, tiles, snow and wind
- Fixing points for roofing materials, such as shingles, tiles and slates
Important Features of Roofing Battens
Although all roofing battens may look almost identical to one another, there can be a surprising amount of differences found between them. In an attempt to help you decipher what roof battens to select out of the ever-growing range, here’s a checklist of features to look out for:
- Timber - The type of timber that the roofing batten is made from is also significant and the species of wood it’s come from should be stamped on the batten. Here at Builder Depot, all our battens are manufactured from European Redwood (PNSY) or European Whitewood to assure durability and quality.
- Grading - By law, a roofing batten can only be labelled as such if they reach BS 5534 standards. They are graded either visually or by machine and, if deemed high-quality enough, will be given an indelible stamp with the standard number; if a batten does not have the BS number stamped on it, don’t risk using it. To ensure It has been graded to BS 5534, every batten must be indelibly marked showing:
- Quality - If in doubt about the quality of your battens, ask your supplier what quality checks they’ve been through. This could be something like utilising a scanner to check for deterioration or having a third-party certification, such as JB-Red which is certified by the British Board Agreement and is also included on the stamp.
- Size - The size of a batten is integral to ensure strength to your roofing job. Any batten that is less than 25mm in thickness can be considered ‘under-measure’ and should be avoided as it risks becoming unstable.
- Batten Colour - Why are roof battens blue? Well, roof battens aren’t always coloured and can be found in a natural wood colour, however, you may also see some blue or red battens available. Nowadays, the colours don’t really mean anything; the original idea behind the dye was to allow graded battens to stand out from the ungraded ones, but producers soon just started adding different coloured dyes to the batten treatment in a practice referred to as ‘kidology’. Generally, the lighter the dye the better the quality as this proves it hasn’t been coloured to hide the imperfections of the wood, but colour alone shouldn’t choose your batten for you. If you’d like more information on this history of batten colouring, SR Timber has discussed the topic in detail.
- Treatment - In accordance with BS 8417, all battens should be preservation-treated to ‘Use Class 2’, however, different manufacturers use their own types of treatment which may result in a different guarantee, such as promises against wood-rotting fungi or insect attacks. If you’d like more information on Use Class 2, the WPA (Wood Protection Association) has collaborated with the Timber Trade Federation to produce a comprehensive guide on Understanding Use Class 2 (UC2).
- Sustainability - Making sure your timber is sustainably sourced has never been more important! Luckily, this is easy to deduce - just make sure the battens have an FSC or PEFC Certification.
- Its size
- The supplier’s name
- The timber species
- A third-party certification scheme
How many roof battens per m²?
In order to hold the average roofing tile, your battens should be fixed to the rafters at a maximum of 600mm apart and should span across a minimum of 3 rafters, as shown below:
If you’d like more information on how to fix battens to your roof, check out Marley’s blog on How to Install Roofing Battens.
What size nails for roof battens?
In line with BS 5534, the nails to use when securing battens to rafters should have a diameter of, at minimum, 3.35mm. The nails should penetrate the rafter at a minimum of 40mm, meaning a nail length of 65mm is generally recommended to take on the task.
There are a few different nails you can use for roofing battens, including round wire nails, felt nails, cut clasp nails, and annular ring nails. If possible, opt for a zinc-coated nail where extreme conditions (e.g. coastal conditions) might be experienced.
For further information regarding the legal standards surrounding roofing battens, please see the Battens Page provided by the NHBC (National House Building Council).
If you’d like more information on what applications treated timber is apt to tackle or what different kinds of timber are available, take a look through our other timber guide pages: