How to make your timber garden shed last forever (or nearly)
“All a shed needs is a good hat and a good pair of boots”
To this slightly modified version of a saying from the county of Devon, in the UK, it could also be added a good rain mac as well.
What is all this talk of wet weather gear in an article about sheds?
Water is one of the biggest enemies of any building, it makes it uncomfortable for the inhabitants and it rots the fabric of the building. There are three main routes to keep the fabric of your shed dry;
1.Maintain the roof well to stop water from above
2.Add a secret ingredient to the foundations to keep the timber as dry as possible
3.Keep the outside of the shed waterproof through using appropriate paints or stains
Maintaining the roof would seem to be a simple matter
Keep a look out for leaks on the inside of the shed roof and when you spot one fix it. However often leaks start well before they are apparent and by the time they have been spotted the damage has been done and a structural piece of timber or a whole section of the shed needs to be replaced.
It is important to know roughly how long your roofing system will last so that you can plan to replace it. The typical roofing felt system that is supplied as standard with many sheds only has a projected life of 5 years, felt shingles have a life of about 20 years and a rubber roofing system can last 40 years or more.
Another way to help your shed roof is to install guttering around the perimeter so that rainwater flowing off the roof is taken away from the shed rather than just falling to the ground and soaking the timber at the base of the shed.
The base of the shed is very vulnerable to water from above and below
Water coming off the roof can make the bottom couple of feet of the shed very wet in a rain storm. Installing guttering to the edge of the roof can reduce this significantly. However if the timbers that form the shed floor are in contact with the ground they can be damp almost permanently.
To limit this dampness through contact with the ground then installing a separating membrane from some strips of PVC Damp Proofing Course (DPC) material will provide a physical barrier to stop migration of dampness. If the shed is built off timber runners then the damp-proofing should be on top of these. The runners should be built of a durable timber such as oak or from softwood that has been pressure treated with preservative. If the shed has been built on a patio or other hard surface it should have a fall so that water will drain away and the DPC will be placed in strips below each of the floor members.
The DPC is only good for protecting the bottom of the shed from moisture in the ground, for protecting the sides of the shed against wind driven rain then we need to look at some paint systems.
The paint system that you use will act like a coat to help the wall shrug off the rain
The best rain coats stop the rain getting in but also allow water vapour from inside to escape, they are said to be breathable. This is very similar to modern stains that are applied to sheds. They have ingredients that help the water to flow away, but if any moisture does get into the wood they are sufficiently breathable to let it escape.
Older paint systems do not allow this to happen and if you look carefully at a timber structure where the paint system has started to crack and let in moisture you will see that this is true. To keep a shed in top condition using traditional paint will require a lot more ongoing care and maintenance than just giving it a brush down and adding an extra coat of stain every three to four years.
Remember to keep your shed in good condition get it a good set of rain gear
The roof is like a hat and keeps out the rain from above. The foundations are the boots that stop damp rising up out of the ground. Using a modern stain is like adding an extra coat of wax to the coat every few years, there is minimal preparation and it is a lot quicker and easier than the traditional methods that require extensive preparation.
Keeping the fabric of timber shed dry will give it many years of life