How to Waterproof a Wood Deck
Many homeowners have an upper level deck with a ground level space underneath they would like to transform into a usable space, but the problem being that water drips through from the deck above. So what is the simplest way to make the underside of the deck waterproof ?
There are of course many under deck ceiling systems which generally work by installing some type of panelling or channelling system underneath the deck , which then drains all water away to one of the sides. Generally these systems are installed by licensed installers so are not normally a DIY option, and the cost can be relatively high. On the other hand one of the benefits of many of these systems is that they can create an attractive lining to the underside of your deck.
But if you are looking for a DIY option to waterproof a deck, that is both quick to install and affordable , then possibly the best option is to use modular interlocking deck tiles on your deck in combination with a waterproof membrane under the tiles . The way this is achieved is as follows.
You purchase a continuous sheet of EPDM which is typically used as a pond liner or as a membrane on rooftops and will provide a wear resistant , long-lasting waterproof membrane. EPDM is available in widths up to about 50′ so you can lay down a complete sheet without any joins over most decks. At the walls of your residence , you need to ensure that water cannot seep down the side of the wall into the space you want to make dry below. The best way of achieving this is to run the EPDM sheet a short distance up the side of the wall as flashing and to fix the EPDM to the wall with an adhesive specially designed for use with EPDM to provide a good seal between the wall and the EPDM sheet.
After you have laid the sheet over the existing deck , then you simply lay down modular interlocking deck tiles over the sheet . These tiles can be purchased in a number of different materials including not only wood but also composite wood, slate, granite, sandstone and porcelain . So if for example you decide you no longer want the regular maintenance required with a traditional wood deck, then you could use the stone or composite wood tiles instead . And in many cases you can mix and match the tiles . So for example you could have a composite wood deck with an infill panel of slate.
And the beauty of interlocking deck pavers is that they just snap together, automatically ensuring accurate spacing , with consistent gaps between the tiles. So even if you don’t have any particular handyman skills, laying these deck tiles is essentially foolproof.
For the perimeter of your deck you can normally purchase edging pieces or transition strips which provide a sloping transition to the deck level and ensure a neat professional finish.
There are however a couple of points you need to take note of if you are planning to waterproof your deck with this particular method. Firstly, since the deck tiles will raise the height of the existing deck about1 1/2″, you need to make sure that this will not create a problem Edit this text with any outward opening doors. The second point to note is that your deck must have a slight slope away from the wall, because now that you are making the underside of the deck waterproof, any water must drain away from your walls.
But apart from these two considerations , you’ll probably find that using interlocking deck tiles installed over an EPDM membrane is one of the quickest, easiest and most economical methods of creating a dry area underneath your upper level deck.