We specialise in wooden shuttering for concrete
Our highly trained carpenters are fully certified CSCS operatives and experts in wooden shuttering. Our team are armed with a vast wealth of experience ranging from industrial concrete slab work, to underpin and structural projects.
- Steel assembly
- Form work
- Reinforced concrete foundations
- Structural reinforcement
- Underpinning & ground works.
We pride ourselves in offering a professional, well-priced service tailored to each project’s individual needs. Because of this, our aim is to complete each building project to the highest standard. We remain on the job until everything is completed and 100% customer satisfaction is achieved. At B A Boyle & Son, we put the onus on quality, and firmly believe that excellent results speak for themselves.
Ready to help
We are happy to consider all types of concrete formwork including domestic, civil, industrial and commercial. Please contact us today and a member of our friendly team would be happy to assist in helping your project move forward.
Formwork & Shuttering
What is formwork?
Formwork is a broad term used to describe the process of designing and creating a temporary mould, into which concrete will be poured, and set. Traditional formwork, also known as shuttering, is constructed using timber sheets, however, shuttering and formwork may be completed using a variety of materials, including plastic, steel, and alloyed sheet metals. Formwork is utilised in both domestic and commercial construction, and most often used in the creation of concrete buildings, slabs, pillars, and stairs, amongst other products.
What is shuttering?
Shuttering is a specific term within the broad description of formwork referring to the process of creating plywood or shuttering wood mould to hold concrete. Timber shuttering is the most traditional, and commonly used method of formworking, with moulds constructed quickly on-site using a specific, water-resistant grade of plywood.
Shuttering can be used to construct walkways, slabs, stairs, and foundations, amongst a variety of products. Though primarily used as a temporary mould designed to leave a minimal impression, shuttering is now commonly used to create a timber impression in modern concrete buildings, such as the Royal National Theatre.
What are the materials used for formwork?
Though the most traditional material used in framework is shuttering grade plywood or timber, reusable alternatives include steel, aluminium, and fibreglass. Formwork may use a combination of these materials to achieve optimum results.
All materials used in formwork must be capable of resisting the hydrostatic pressure of freshly poured concrete, with the base responsible for holding all dead loads. In addition to this, it must be easy to construct on-site and to remove after the drying of the concrete. Stabilisers are often used in framework – existing in the form of traditional beams. These beams tend to be re-used.
When can formwork be removed?
The removal of shuttering or formwork from concrete after setting is generally referred to as ‘stripping’ - with the period between concrete pouring and removal dubbed ‘stripping time’. Stripping time varies greatly depending on the laud of concrete, position of forms and conditions the concrete is subject to. Stripping time is also heavily influenced by the grade of concrete used.
In the case of an average slab, shuttering may be removed after approximately 24 hours, but the concrete itself should otherwise be left undisturbed for at least three days to allow for proper setting. To contrast this, beams should be left in formwork for at least seven days.
What is shuttering plywood?
Whilst regular plywood is a wooden sheet constructed by layering thin wooden veneers and glue, shuttering plywood is a specific grade of plywood manufactured specifically for use in formwork and shuttering. This plywood is commonly used in the creation of moulds used to house poured concrete – meaning it must be water-resistant, and will not stick to wet concrete. This is achieved through the use of a strong adhesive in place of regular plywood glue. Generally, shuttering plywood is available in thicknesses ranging from 7mm to 32mm, and can be reused so long as it is cut into a generic shape.
How do I stop concrete from sticking to plywood?
The best way in which to prevent concrete sticking to plywood is to ensure you are purchasing shuttering grade plywood – a material specifically manufactured for formwork using high strength adhesive materials and designed to prevent concrete sticking.
Using any other type of wood or plywood will most likely result in sticking to some degree, as concrete does adhere to wood. This being said – the application of oil is thought to prevent concrete from sticking to wood. This is generally sprayed 15 to 20 minutes prior to pouring concrete. Though generally effective, this solution may be expensive compared to investing in shuttering grade plywood.
How long should concrete be left to set before removing forms?
Forms, shuttering, or moulding, should generally be left in place for at least three days to ensure the concrete is suitably dry. If forms are removed early, concrete may sag, crack, or collapse, especially when exposed to adverse conditions. Concrete should be left for an additional three days to allow for further curing. After seven days, the vast majority of industrial concrete mixes will have gained around three-quarters of their compressive strength – this will continue to grow within its 28-day curing period. Heavy vehicles should not generally be used on concrete until the end of this curing period. This also applies to domestic mixes – though timings may vary slightly.
How long does concrete take to set?
Setting time varies depending on concrete grade and application. The majority of industrial-grade concrete will have achieved its full compressive strength after 28 days of curing in suitable conditions. Domestic concrete tends to be reasonably set within 24-48 hours of pouring or laying. It is however recommended that no heavyweight items (such as cars) are placed upon it until the end of the same standard 28-day curing period seen in industrial concrete.
What is the best concrete mix?
There is no ‘one size fits all’ concrete mix. Different brands and grades are developed and used for a variety of applications, with each of these requiring a slightly altered mix. For example, concrete produced to be poured into a custom or awkward foundation or form must have a higher slump (or be more free-flowing) in order to allow all gaps to be filled easily. A high-slump foundation is generally produced using a higher ratio of water to aggregate, and often includes a plasticiser – so, mixes fitting these requirements are best for awkward forms. Road-making requires an extremely low slump mix as a result.
Is concrete waterproof?
Most concrete is not entirely waterproof, because the majority of concrete mixes available on the UK market requires the addition of a significant amount of water in order to modify slump levels. Excess water generally evaporates during the setting process, leaving small porous areas on the concrete’s surface. These pores or capillaries are able to absorb water – slightly affecting the ability of the concrete to be waterproof. This concrete can be made waterproof by applying and regularly maintaining a waterproof sealant.
To contrast this point, there are watertight and waterproof variations of concrete, which are commonly used in basements.