Second Story/Waterproof installation
Follow all local and federal building codes when installing Aeratis Porch flooring and Ceiling products.
Before you begin, please note the two key elements to having a successful waterproof install are slope and the direction of the boards. Make sure the slope is no less than 1/8″ per foot (some building codes require a 2% slope of the overall length). The installation is best if the slope is 1/4″ per foot. Also, make certain that all the boards are running the direction that you want the water to run off (run the boards perpendicular to the structure). Try to avoid all butt joints in a waterproof install. If butt joints are required, make sure to acclimate the boards properly (see installation instructions for acclimation requirements for butt joints) by using one of the recommended PVC cement products and make sure you use screws to secure the end of the boards securing the butt joints.
PLEASE NOTE: make sure you are not attempting to float a pressure treated frame on top of a membrane. In many cases, when contractors try to do this and cannot fasten the frame through the membrane, the wood buckles and twists over time creating an uneven flooring surface.
Installing your Joist
The perfect 2nd story or waterproof installation consists of joist installed at 16”OC, 1/2” or 3/4” pressure treated or marine grade plywood, a waterproofing membrane (Grace Ice and Water Shield HT or equivalent… for an equivalent, you must be able to penetrate the membrane while it still maintains it’s warranty), 5/4” PT Pine decking or Douglas Fir strips for a sleeper system and your Aeratis boards. Variations of this installation will be discussed later to help accommodate for spacing issues. If you have the ability to plan ahead and can make space for the perfect installation, make sure you leave enough space from top of the joist to the bottom of any outward opening doors for all the materials listed above (no less than 4-5/8”).
Before you begin, make sure you measure from the threshold down to the top of your joist. The ideal amount of space is 4-5/8” inches (from the threshold to the top of the joist, this allows room for using 3/4” plywood, waterproof membrane, crisscross 2” x 4” pressure treated sleeper system and your Aeratis boards). If you do not have this much space available we will cover how to install with a smaller amount of space below.
Once you have the proper measurement and have allotted for the space needed for the perfect install, begin your installation by installing your joist 16” OC. Your joist can be installed either parallel or perpendicular to the structure. You can make this decision based on your individual needs. Make sure you allow for proper slope away from the structure. We recommend 1/4” per foot on structures less than 13 feet deep and 1/8” per foot on structures deeper than 13 feet. Once all the joists are installed at 16”OC you can begin installing the plywood over the joist. It is best practice to use pressure treated T&G plywood when possible. If T&G is not available, then standard square edge plywood will work. Begin by fastening your plywood down to the joist by using a construction adhesive on the joist and fastening the plywood down with screws or staples (check with the wood treater for the best type of screws to use to fasten down the plywood to the PT joist).
Once the plywood is installed, the next step is the membrane. Begin installing the peal and stick membrane from the outside edge of the porch. Follow the installation instructions of the membrane. Once you get to the edge of the house, make sure you turn and run the membrane up the house as far as possible. If your wall is brick, make sure you use the proper flashing and seal up the transition between wall and floor to stop water penetration.
Next step will involve your sleepers. Your first or bottom row of sleepers should run perpendicular with the walls of the house. They should be spaced at 16” OC. Each sleeper should be anchored to a joist every 16 inches. The second row of sleepers should run parallel to the wall crossing the bottom row of sleepers creating a crisscross or X. This will allow any water that penetrates the T&G flooring to easily run out from under the sleeper system.
No Room For Sleepers?
If you do not have room for 2 sets of sleepers or a crisscross sleeper system, you can simply use one sleeper. You will want to run your single sleeper system parallel to the house. On the bottom of the sleeper, you will want to cut notches or channels in the bottom of the sleepers every 12 to 16 inches. This will allow the water to run under the sleeper and escape out of the soffit vent area. If you do not have room for one row of sleepers, you can fasten Aeratis directly over the Grace Ice and Water shield HT product. If you are fastening directly to the membrane, you MUST make sure that each fastener penetrates Aeratis, the membrane, the plywood and the joist (3-1/4” screws should be used). Fastening Aeratis to the plywood alone may not be sufficient for your long-term waterproof application. Also, in this case, it is highly recommended that you use a 1/8” bead of 100% paintable silicone in the groove at the time of install (wipe up any silicone that squeezes out. It will not bond to Aeratis, but can be a visual distraction to the project).
Parallel vs. Perpendicular
It is always best practice to make sure your Aeratis boards are run perpendicular to the structure. (Make sure the boards are running the same direction as the desired direction of run-off water.) Running the boards PARALLEL WILL NOT VOID THE WARRANTY. However, if you are running the boards parallel, you will want to make sure you pay close attention to acclimation. If you are installing Aeratis parallel to the structure, you are required to glue all butt joints with the Aeratis approved glue. Make sure you order the PVC glue at the same time you order your Aeratis boards. YOU WILL HAVE TO SQUARE THE ENDS OF EACH BOARD BEFORE INSTALLING IN AN APPLICATION USING BUTT JOINTS.
Fastening for Waterproof Installation
It is best practice to use both fasteners and joist/sleeper adhesive for a waterproof install. Ensure that you do not leave any gaps between boards. Use a urethane-based adhesive for connection between Aeratis and the joist/sleeper system. It is not required, but it is best practice to use a stainless steel fastener. This is more important in a waterproof installation.
Make sure you account for water getting under your Aeratis boards and on top of your membrane. Your membrane, if installed properly will keep the water out of your living space. Ensure you provide a way for the water to exit the area and that you are not damming up any water.
It is best practice to ventilate your wooden structure. Keep in mind, wood is an organic material and is subject to deterioration if it is installed in an overly wet or dry condition. If your joists are kept too wet or moist, the holding power of the fasteners could be compromised. If the wood is kept too dry, dry rot can occur and your fasteners can fail.
If you have any question whether or not your specific application will be warranted, you can fill out our pre-installation warranty on the Aeratis.com website. If your installation is not approved, a member of our staff will contact you with suggestions of how to modify your install so it is completely warranted.