deck over existing cement slab. usually when a deck is that low to the ground the hardscape options are always the best, from a durability standpoint. you want air flow under the deck and cross ventilation, so the framing and the under side of the decking will dry out. most synthetic decking manufactures like to have a 12' air space.
ripping up concrete and building a deck seemed like a daunting and expensive task, so when we saw newtechwood deck-a-floor, we thought it would be absolutely perfect for our space. within a day, our concrete slab went from drab to fab.
a concrete slab is one of the basic components of modern construction throughout the world. whether used as a building foundation, sidewalk, patio or a mounting pad for your ac condenser, the method of construction is largely the same. building codes generally require that exterior stairways have a concrete footing or foundation.
i've built new sloped concrete decks over membranes before, with many years of trouble free use, but this is a renovation of a flat wood deck. this time, i'm thinking about putting a concrete surface on top of the existing cedar decking. the cedar is in pretty good shape, with just a few boards showing a bit of rot.
a typical pad has a 4-inch layer of gravel underneath and about 4 inches of concrete on top. when building a landing for deck stairs, typical codes require the pad to extend beyond the steps about 36 inches, behind the steps about 12 inches and on the sides of the steps about 6 inches.
one of the things to watch out for when building a deck over a concrete slab is water drainage. building so close to the slab means there isnt much room for air to circulate underneath the deck, and this can trap water. the last thing you want is for that water to flow toward the homes foundation.
re: building deck on top of concrete patio. placing the joists directly over a slab on grade sog isn't a great idea. you'll trap moisture below the deck boards, along with all manner of organic material which will turn into a compost heap or sess pool. the neighborhood mosquitoes will love you in the wet months.
mark out positions for the base plates on the concrete slab see table for minimum span requirements for various width joists these are all based upon continuous span with joists at 450mm between centers.
one is to place 'sleepers' or treated joists over the concrete slabs adjust the heights to account for the differences in the slabs to make them equal in height . they are called sleepers because they rest on the concrete. you would then cover the sleepers with either deck boards or a high quality exterior plywood.
ground level deck. free standing decks may use floating pier blocks which allow the deck to move along with the ground. some builders build ground level decks directly on top of existing concrete patios using sleepers. here is an example of a ground level deck.
building a wooden deck over a concrete one: so we've had this very sturdy but extremely plain looking concrete porch in the back of the house, and we've always wanted to make it warmer and more inviting. the obvious solution, to us, was to replace it with a wooden one. wood is by far warmer
build a timber deck over concrete. you cannot simply screw decking boards directly to the concrete slab itself. you need to have battening in place for the decking to sit on. this allows air to flow through the structure and it helps to level the height. the battening also protects the timber from direct contact with the chemicals in the concrete,
the top surface of your slab should be about 5 inches off the ground. this will allow your siding to overhang about 1 inch, then provide a 4 inch gap between the ground and the untreated wood siding. this 4 inch gap is your best defense against termites and moisture getting to the shed. and often times this is in the building code.
in comparison, a 4-inch-thick slab of concrete weighs about 45 psf, which makes it almost neutral in these types of winds thanks to its own mass. another benefit to a concrete deck is that it's inherently dry underneath, while a wood deck has gaps between the deck boards that allow water to run through to the lower areas.
build a timber deck over concrete. concrete is a versatile and durable flooring material, but in time it can end up in pretty bad shape. how do you add life to a tired, old, cold and dull slab of concrete? why not build a timber deck on top of it?
hide ugly deck board ends: 16 modern deck building tips and shortcuts there are lots of new decking products on the market, and deck building methods continue to evolve and improve. here are some of the best tips and products for a great looking deck that will last decades. install flashing approved for pressure-treated lumber on top of the ledger.
installing decking boards on top of concrete prevents air from circulating evenly across all four sides of the wood, leading to rapid changes in only one side of the board. this uneven release of moisture causes cupping, warping, and twisting. concrete tends to retain moisture and heat much longer than other materials.