Call backs for squeaky floors can be extremely costly and time consuming. When squeaks originate in the sub-flooring, these call backs can really eat into your already slim profit
margins. Here are some tips on installation techniques that can help to prevent the dreaded squeaky floors.
Adhesives
Select sub-floor adhesives according to the standards set for them. PL-400 sub-floor adhesive meets that standards but if you select another one make sure it meets the minimum standards for your end use to ensure it is strong enough and will maintain its bond over time. Always read the instructions, especially regarding the temperature ranges it can be used in.
Only apply enough adhesive to install two or three panels at a time. This will avoid the glue setting too soon. When glue sets too soon, the panel may not set down flat on the joist and that will create an uneven floor. If you glue the panel down you must completely fasten that panel before moving to the next one. If you don’t and the glue sets, it will be almost impossible to get the panel to lay flat. Lay the adhesive in a zigzag pattern down the joist and then lower the sub-floor panel down on the joist. If you have used enough glue, you should see it squeeze out between the joist and the panel.
Note that some I-Joist producers require sub-floor adhesive to be used and the National Wood Flooring Association has these requirements as well. Adding a small bead of glue to the groove of the sub-floor panel will also increase the strength and stiffness of the floor.
Proper panel spacing
The 4’ ends of the sub-floor panels must be spaced 1/8 inch apart. This spacing allows them to expand and contract with changes in ambient moisture and can help reduce ridging. When panels have space to move the risk of deflection caused by expansion is reduced or eliminated. To further alleviate expansion, allow the panels to acclimate to new environmental conditions prior to installation. Lightly butting the T&G together is the correct way as forcing them can result in damage to the panel or the tongue and groove.
Always consult your local building codes for fastener spacing, size and type and follow the manufacturer’s instructions as well as your design professional’s specifications. The APA construction guide E30V is a great resource and offers many useful tips.