Shuttering ply is a special type of plywood, designed specifically for concrete formwork. This is the process of building a supported frame which concrete can be poured into.
The formwork structure is temporary. It is created to hold the concrete in the correct dimensions, whilst it sets to hard concrete. once the concrete has fully gone off, the supports and shuttering ply can be removed.
Shuttering ply, and formwork in general, can be used to build a variety of different structures using concrete. Some of these include:
- Concrete slabs
- Concrete staircases and steps
- Entire buildings
Essentially, anywhere that concrete is used to build a structure. Shuttering can be used to contain the poured concrete. This will then remain in place until the concrete is hard enough to hold its own shape.
There are multi story structures built on a regular basis, that are made almost entirely with concrete. When all this concrete is poured, it needs to be poured into something, and this is the job of shuttering.
Usually shuttering ply is used in combination with an array of supports and props to hold it in place.
Shuttering plywood vs plywood
There are several differences with shuttering plywood and standard ply. Firstly shuttering ply is far denser. It is constructed using more layers of highly compressed timber.
This enables it to support a much higher load than standard ply. A sheet of 18mm shuttering ply, can support several hundred kg per cubic meter.
It is also WBP (water boil proof). This is due to the glues used in its construction. These glues make the finished sheet far more resilient, to both high levels of moisture, and extreme changes in temperature.
Here is an example, to give you an idea of what this means in terms of durability:
When submerged in boiling water, a standard sheet of plywood will last roughly 4-8 hours. whereas a sheet of shuttering ply would last far longer before de-laminating (up to 72 hours).
As you can see, the shuttering ply will perform much better under high temperature and moisture.
Another difference is the boards finish. Shuttering ply will often have a smooth film face, usually made from a phenolic resin. This provides a smooth finish to the concrete once the plywood is removed. It also provides an additional layer of resistance, to moisture and corrosion from the concrete.
Finally, due to its durability, shuttering ply can be used multiple times in formwork before it needs replacing. Most boards will last for around 10 applications before they need to be replaced with new sheeting.
A standard plywood would simply not hold up to the job. The board would deteriorate due to moisture. Also, it wouldn’t be able to take anywhere near as much weight, and the finish would be poor. This is mainly because the surface isn’t as smooth.
How much does shuttering ply cost?
As with most things in the construction industry, the price can vary widely from one supplier to the next. Generally, you will get the best price from a local builder’s merchant, that regularly stocks shuttering ply.
Generally, for a standard 18mm sheet of shuttering plywood (1200mm x 2400mm) you should expect to pay somewhere in the region of £30-£35.
For a higher end board, with a phenolic film finish, the price will go up a bit. For a board with the same dimensions you would be looking at around £45-£50 per sheet. Whilst this is quite a bit more expensive, it is a better product.
With the phenolic faced plywood, you will get a better finish on the concrete and the boards will potentially last longer.
As you can see, shuttering ply is a specially made product. It is specifically designed to contain, and support poured concrete. This means that it has several characteristics not found in standard plywood.
It is far more durable and can withstand high pressure from concrete, as well as excessive levels of moisture and temperature change.
A standard plywood would not be suitable for this type of work. Also shuttering ply is relatively affordable. It is similar in price to standard plywood and considerably cheaper than a high-quality marine ply.