Browse Forums Paving & Concreting 1 Apr 25, 2014 1:32 pm Hi! Just after some advice regarding drainage of water from under a timber deck. Our slab to our new home has allowed for a outdoor entertaining area under the same roof. We thought it would need a slight slope or drain to allow for drainage of water, neither have been done. I assume over time we will have problems with the timber deck as any water accumulating under there will just "sit" until it dries out. Any recommendations as to what to do or if you think this will be an issue?? Thanks! Re: Concrete slab under timber deck.....Drainage?? 2Apr 25, 2014 5:27 pm I'd sit the deck slightly off the ground, it won't need much use some squares of 5mm plate steel squares (the big green box sells all this stuff). This way the water can sit until it drys up. Re: Concrete slab under timber deck.....Drainage?? 3Apr 25, 2014 8:48 pm I find it hard to believe they would poor an integral alfresco slab with no fall at all, have you taken heights over it or just going by eye. If it is flat then yes packing it would stop the battens sitting in water for extended amount of time, a 75x50 hardwood batten would need something every 450mm or else it will be springy. Also look at something corrosive resistant rather than steel. personaly id sit it on the concrete before putting something that will rust away under it. Re: Concrete slab under timber deck.....Drainage?? 4May 04, 2014 11:07 pm Thanks guys, Yes the slab is flat. We have been advised we can treat the underside of the timber with a type of waterproof solution. Im assuming the deck will sit on battens. We can also drill holes into the slab to create drainage....huge no no for us. I wouldn't want to drill holes as im sure the engineer wouldn't be impressed and we are in a termite prone area so this is not an option. thanks for advice Re: Concrete slab under timber deck.....Drainage?? 5May 05, 2014 7:20 pm you could also use the newer engineered composite decking for battens, they are extremely water resistant and the higher density gives a perfect medium to screw your decking boards to without worrying about splitting later on (only requiring a predrilled pilot hole beforehand) Re: Concrete slab under timber deck.....Drainage?? 6May 29, 2014 7:01 pm Screed sand & cement to ensure a fall, Use plastic packers to keep battens from surface Coat underside of decking with paint (similar color), this will reduce cupping close to the ground. Landscape Design & Construction http://cherub.squarespace.com/ 13 4645 Thanks for the insights, that makes perfect sense, and yeah, I will be leaning on the experience of the excavator operator entirely. 6 11041 4 4004 |