Why do wooden gates warp?
It is woods nature to do so. The characteristics of wood affects how it reacts in different circumstances. However, certain easy measures can be taken to minimise the effects of this happening in the first place.
– When it is wet wood will absorb moisture
– When it is dry wood will dry out.
– All wood moves.
– Fixing wood to a metal frame will not stop wood moving.
– Pressure treatment will not stop it either
– Hardwood’s can bend and twist just the same as softwoods
So what causes your wooden gates to move opposite directions!
There are several causes of why wooden gates move but the most common reason is the wood drying out.
When a tree is first felled the timber is called green, and refers to the fact that the tree has not dried out and is very heavy and very wet as it is full of water. This timber needs to be dried out before it can be used effectively. Most timber these days is kiln dried. Quality wooden gates are made from timber where the moisture content has equalised with the surrounding humidity. The wood for our Courtyard & Driveway gates is dried to 16%. This timber is therefore stable and suitable for external use.
However, the gates once outside will adjust to their surroundings. So for example, for a gate in the winter the moisture content of the air will be around 20%. The gate will therefore absorb moisture. Then onto the summer where the moisture content is lower and the water will evaporate from the gate.
If your gate is south facing then one side is going to dry out more than the other side is, as one will be in sun and the other shade.
This means, unless the gates are treated correctly, as the wooden gates dry out one side it will shrink and therefore bend towards the sun. If one gate had more moisture in than the other then this is when you get one gate bending more than the other.
If a gate is under a tree then it can be in shade which is good as it does not dry out too quickly. On the flip side in the winter the gate can also get very wet as it is constantly dripped on in the rain. As it is in the shade it never dries off. Often you will find this is when green moss develops on the gate it as moisture in the timber soars over 20% allowing the decay process to commence.
This all sounds like bad news!!
However, there are solutions to these problems which can help prevent gates from warping!
Firstly, making sure the gates are correctly installed. Click here for our recommendations. By using the correct fittings it will give you a good starting place. Gate fittings play a crucial role in the movement of gates as they facilitates the easy opening or closing of the gate. The size of the hinge is important as well. A rule of thumb for gate hinges is that the hinge length should be one third of the width of the gate. An important consideration when hanging a gate is the weight, the width and what it is going to attach to (post, wall, pillar, etc.). As the gate gets heavier and/or wider, the hinges need to be more substantial.
It is important to make sure if the gates are installed near a hedge to keep the hedge well trimmed. If a gate is left open for extended periods against an over grown hedge it can put pressure on the gate that could cause movement in the wood.
Secondly, treat the gates with a modern UV oil for more information click here.
The benefits of oil in the protection of wooden gates
Surface coatings, such as paint, lie on the surface of the timber preventing the ingress of moisture into the timber (which is the cause of rot and decay in timber).
However, if the gates are too wet when they have been painted then you are essentially “trapping” the moisture into the wood and it will start to rot underneath the paint. Paints are also susceptible to cracking and chipping which can let moisture in. It is for this reason we do not recommend paint as a finish for our wooden gates.
Using oil on timber solves these problems and has significant advantages over surface coatings:-
- Oil penetrates the timber and fills the microscopic holes as it is absorbed into the wood.
- Moisture will be repelled by the oil in the timber. Therefore eliminating much of the absorption and evaporation that can case wood movement.
- Oil is quick and easy to apply and relatively low maintenance compared to other coatings.
The images below show how movements in wood are reduced when using oil. There are less checks and shakes and water absorption.
Our Tongue & Groove gates are designed with and expansion gap to allow the boards to shrink & swell during different weather. In very hot weather when the boards will shrink you will be able to see this moment on a painted gate (as image below). The boards will swell when there is more moisture and should return and close the gaps.
Treating a gate with oil will help reduce the movement in the tongue and groove boards.
Wood oil is easy to apply and will sink into the timber and repel water that will fall onto the wooden gates keeping out the moisture and extending their life. If you want a colour (for example on a softwood gates) then tinted oils are available.
When applying the oil let it sink in & keep applications going on until the timber cannot take any more. Do this over the first few months after you have hung your wooden gates.
In subsequent years, all you have to do is top up the oil in the timber at least one a year. But if we have a very hot summer then another application may well be required.
Yes wood requires a little work, but looks so much better that their metal and composite counterparts. Oil preserves and enhances the natural colour of the gates.
A small amount of effort is well worth it!