Sheds are usually measured in feet and inches, and are produced in many different shapes and sizes. The most popular sizes are 6×4, 7×5 and 8×6. As these sheds are manufactured on a big scale by a wide range of producers, they tend to cost less than more unusual sizes.
Shed walls can be divided into two main types: overlap and shiplap. Overlap sheds are the easiest to produce, and therefore the most cost-effective option. Their walls are made up of horizontal overlapping planks which form a series of sloping surfaces, like tiles on a house roof. This simple but effective design lets rain quickly flow off the shed walls before it gets a chance to soak into the timber. An advantage of this design is that if an individual plank gets damaged, you can quickly slot a new one in place without having to disturb any surrounding boards.
Shiplap sheds have a higher price tag but are sturdier and more weatherproof. This is because the wall planks are shaped to tightly interlock with each other. They also have an extra lip, or groove, between each panel to help rainwater run off easily, making them twice as watertight. In addition, these sheds are often made from superior timber which has been slow-grown for extra strength.
There is a third type of wall, also at the premium end of the market, which is often referred to as shiplap but is not quite the same: tongue & groove. While this is very similar, with a secure interlocking construction, it does not have the extra lip between each board.
Check the thickness of the walls, roof and floor before making a choice. Ideally they should all be at least 8mm, and preferably 12mm. The roof and floor in cheaper sheds are nearly always made of chipboard (also called OSB, short for oriented strand board), whereas in high-priced models they are likely to be solid wood.
The cheapest type of roof covering is black mineral felt. It is also the thinnest, so needs careful fitting as it can be easily torn. Green mineral felt is thicker and more durable, but costs a little more. Both types are normally supplied in rolls, and have to be cut to size then nailed in place along the roof frame. Corrugated roofing sheets made from bitumen are also becoming popular, but are much more expensive.
Sheds are made with roofs in two main designs: apex (shaped like an inverted V) and pent (a single flat sloping surface). Both types cost about the same, but it’s a bit easier to fit covering to a pent roof as there is no centre ridge involved. You can also get reverse apex sheds, where the door is set in the long side wall instead of the front, but as these are less common they tend to cost more.
You may have noticed that not all sheds are the same colour. This is due largely to the timber treatment used by the manufacturer to protect the shed from rot and insect attack. There are two types:
If cost is your main priority, choose a dip-treated shed. During production, all the wooden components are immersed in a tank of preservative – a speedy, low-cost method of treatment that leaves the timber an attractive golden brown colour. The only downside is that the preservative wears off over time, so the shed will require re-treating every couple of years.
Sheds manufactured from pressure-treated (also known as tanalised) timber are more costly, but the treatment is extremely effective and in some cases can last up to 15 years before any re-coating is needed, saving time and money in the long run. This is because the process involves pumping powerful preservatives into the wood under vacuum conditions so that they penetrate deep into the grain, giving excellent protection from moisture and parasites. The treatment gives the timber a greenish tinge that eventually fades to a silvery grey, but you can re-stain it if you don’t like the colour.
Last but not least, we come to the base – often neglected, but a vital structural support that will keep your shed off the damp ground and help it last longer. Nothing beats a concrete base for strength and durability, although even if you can lay it yourself it’s not a particularly low-cost choice.
To save money, consider paving slabs or a wooden base anchored by spikes, which you can buy in kit form or make yourself. Plastic bases are also available, but are much more expensive. Whichever one you choose, make sure the surface is completely level before installation, otherwise the shed will soon start to warp.