Install decking on concrete

Why fight nature? Go with the flow, baby. All it takes is a small amount of debris or dirt to clog a weep hole to render it useless.

If a design using weep holes for drainage must be used, then provisions for cleaning out this area should be considered prior to installation. The most important considerations when selecting materials for sleepers are:. Recycled plastic lumber is often used for sleepers because it is rot resistant and should last as long as the decking material and the rest of the deck structure.

Durable hardwood lumber sleepers work well, too. If pressure treated lumber is used for sleepers, the grade and durability of the material should be considered prior to construction. Careful consideration should be given to how the sleeper will be fastened to the substructure. It is important to select a fastener that is strong enough and will last as long as the entire structure.

In a rooftop application, limiting or preferably eliminating all perforations in the roof membrane are important design considerations. Proper ventilation is a critical success factor in the long term design, construction and life cycle of a deck.

Proper ventilation helps the wood decking to acclimate properly and move with changes in the EMC Equilibrium Moisture Content of the particular job site environs. Failure to properly ventilate a deck can result in deck boards that do not dry out and is an open invitation to mold, mildew, algae and fungi.

Mold, mildew and fungi are not only unsightly; they can create rot and decay problems on and around the deck structure. Since ventilation options are minimal on a deck being built so close to the ground or substructure, great care should be taken to maximize the air flow in the design stage and also during construction. While it is true that concealed fasteners can be used effectively in deck design, we believe that the best design and construction practice for a sleeper deck should use screw fasteners.

Screw fasteners will provide stronger lateral bracing for the entire deck structure. Equally important in a deck design being built on sleepers is making sure that the deck boards are securely fastened at the edges. Do not wrap the beam as that will seal in the water, but a folded piece under the beam will help to protect the beam from rotting.

Preventing the beam from rotting when low to the ground resting should be a primary concern. The beam rots, the deck is lost it is that simple. I have written more about protecting beams from rot and additional measures to protect not only the beam in contact with the footing but the entire beam. To learn more, click here. The height requirement is to keep the beam and post out of water and dirt. Both are a source of wood rot. It will require a lot of work and removal of dirt by advantageous.

Not a substitute for separation, but installing landscape fabric under the deck and beam will help to limit ground contact between the wood and the dirt. Dirt is terrific but it does contain a high level of rot causing fungi.

The fabric helps to prevent the soil from splashing on the wood during a rainstorm protecting your deck. This is a good idea in that concrete post will outlast a wood post. As always, care must be taken to ensure the concrete footing is at the correct height below the beam. A good idea is to slightly cone the top of the concrete around the saddle aiding in runoff, keeping the beam dry. Additionally, rebar should be added to the footing vertically.

A concrete footing buried in the ground is supported on all sides from lateral pressure. But a footing extending above grade will have additional lateral pressure, the rebar will reinforce the footing. Rebar and concrete are a fantastic team. Ouch, like really? You checked it three times, right? Unfortunately, it happens, I must admit I have placed footings to high for beams. Super embarrassing but no the end of the world or even your deck.

I minor set back that can be overcome. Adjust base-plate in the slot if required. Attach joist support onto hex bolts and adjust to approx height required. Semi-tighten nuts - this will tighten the whole structure enough to withstand joists being inserted and secured. Adjust joist to correct height using dumpy or laser-level or string line.

Note - you will need to loosen the nuts off if the joist support height needs adjusting. Insert joist into joist support and secure with minimum 2 of 25mmx 3. Tip - when fixing nails, brace the other side of the joist support with your foot to minimise vibration. We quite often find that people have miscalculated the number of adjustable joist support required for their decking area. We believe the main cause of this is that people work out the length of their joists, and simply divide by the "support spacings" taken from our span table they have decided on between the supports - eg - having a 3 metre length joist with spacings of 1 metre to give 3 supports.

Similarly, when working out the number of joists required, you need to work out the number of "joists spacings" along your deck and remember to add one for the initial joist. The answer is yes but, first, we suggest you check with your local building office for any code requirements.

Here are a few key factors to consider when building a deck over concrete. Cracks and craters with minimal growth may still be covered without issue, but be cautious if an area of your patio sinks year after year.

Ground-level decks over a concrete patio are particularly susceptible to moisture build-up, so hard-working water management and air circulation is a must. Thinking of being your own builder?

Take note of these deck-building basics before you get started.