Spring is right around the corner, so now is the perfect time to get your new deck designed and built before barbeque season begins. If you have never built a deck before, you should learn all about what causes deck boards to split before you begin. Not knowing the right way to put deck boards down could mean having to replace them months after the finish of the project. Since this is a waste of both time and money, getting it right the first time will save you hours of frustration. Stress and moisture are the main culprits for causing deck boards to split, so keep these points in mind so you can prevent splitting from happening.
Prevent Moisture in Deck Boards
While there are numerous ways you can waterproof your deck boards, such as sealing the boards and laying membranes over the joists, a small amount of moisture will still penetrate into your wood. Because there is moisture in your wood, it will expand during the summer and contract during the winter. This expansion is one reason why deck boards split, but there are several ways you can fight back against moisture expansion:
- Ensure there is plenty of ventilation around and under the deck boards. If you are going to put side walls on the deck, don't use a solid material that will prevent cross-flow air from going under the deck. Additionally, don't build your deck directly on the ground as this also prevents the air from swirling around the deck boards.
- Do not butt each deck board up against the next one. Not only does this prevent air moving between the boards, but it also gives the board nowhere to go when it needs to expand. During the winter, a deck board may expand up to 5% of its width when it absorbs moisture, so a gap of at least 3mm will give the board room to move without it pushing against the one next door.
- Keep sealing the boards even after the building is complete. Before you build the deck, all edges of the deck board must be sealed to keep out the moisture. An oil-based timber sealant will help keep water out of the wood as oil repels water. It does take longer to dry than a water-based sealant does, so bear this in mind when you are preparing your boards. When you reseal the boards each year, you will continue to maintain a high moisture barrier.
Once you know how to keep the moisture out of your deck boards, you need to consider the other common splitting factor which is stress.
Eliminate Stress in Deck Boards
When deck boards are under too much pressure, they will split and break. There are two main ways you can prevent this from happening on your new deck:
- Pre-drill pilot holes in the boards for all screws or nails before you attach them to the deck. When you hammer straight into a deck board without predrilling a hole, you are placing enormous pressure on the board when you hit it with the hammer. This motion weakens the internal fibres of the board which will cause it to split once the board begins to contract and expand due to moisture.
- Make sure there are plenty of support joists under the boards to evenly distribute the load when walking on the deck. The further apart the support joists are, the more stress each deck board is under when it is walked on. If you do not know how many support joists you need, a deck builder can help determine this based on the size of the deck you are building.
Because you do not want your newly built deck to fail, getting advice and building assistance from a deck builder will ensure you achieve a strong, long-lasting deck. The stronger it is, the more summers you will get to enjoy using it.