“We have SolarBord decking under Tru Slate. It weighs around 550 lbs. per square foot. We are replacing it with Spanish tile that weighs close to 1000 lbs. per square foot. Our rafters are on 24″ centers. Is the SolarBord capable of carrying that load?”
Terry Allen, Oklahoma City, OK
Thank you Terry for your question. Table 30 of the APA Engineered Wood Construction Guide provides recommended load span information. The data in the table is based on 10 pound per square foot (psf) dead load. If actual dead load is greater than 10 psf the allowable live load is reduced proportionally. At 1,000 lb per square it equates to 10 lbs. per square foot dead load. Use the table and the thickness of the roof sheathing to determine what the allowable live loads are and if you are unsure, contact a professional designer to get their opinion because other variable may come into play. If you are going to change products – be sure to check that the structure below will support what you are doing.