Decking over grass

Peteemax

Hi everyone,

I'm going to do a decking over grass.
The problem is im not to sure how to prepare the grass area.
ive been told to concrete it or put plastic down on the grass and then hardcore on top of the plastic.
Cant find any good sites.
Any info would be great.
Thank you.

Pete

The Sweeper

What's the clearance height between your ground level and the level you want your deck at?

Peteemax

about a half ft or so.

The Sweeper

And are there going to be gaps where anything larger than an insect will be able to get under your deck? (Sorry for oddly specific questions.)

Peteemax

i dont think so.

The Sweeper

Okay. Things you can do.

You can remove all sod (not as difficult as you think) and compact the earth beneath the deck-to-be (you can use a whacker plate or you can use a board with a loop of rope, one end tied to each end of the board - you put one foot on the board, and press down while pulling up with the rope - works, though not as neat as a whacker...). Now, eventually, that earth will again seed, and weak, mealy weedy things will try and make their way towards the light. Will they reach a foot? Maybe...

You can lift the sod and put down plastic, or weed-weave material and mulch, or sand (persistent weeds will still grow through) or odd mismatched pavers...

The upshot is I, personally, think you'd be mad to spend any considerable money on a weed barrier between the earth and the deck, but if you can lift sod and then use a relatively cheap barrier that would help.

Even look at collecting a half-used pallet of bricks (house bricks, not cavity blocks), and have them smashed into 'pebbles' - up to 1" cube. I find that buckets of those are brilliant - they're heavy, and make a great weed barrier, but also won't be washed away from banks or inclines if used as a mulch.

The reason for the question re accessibility of under the deck is that small to mid sized animals (mice, rats, stray cats) will often access the dry, warm area that is the underside of a deck to have their little fuzzy vermin progeny. They're more likely to do that on, say, lovely wood chip over weed barrier, and less likely to do it on broken brick or scree. If you don't have under-deck-access, you may well get away with lifting the sod and putting down gravel.

The last aspect is what kind of decking board - if you're leaving light-bringing gaps, I'd be obliterating all chance of weeds with a mesh barrier. If you're laying close-fitting deck, then below will be deep, deep shade and could be treated accordingly...

Peteemax

thanks for your reply sweeper it was very helpful.
More helpful than any site i was on.
i will let you know how i get on and post some pics.
Thanks again.

The Sweeper

Peteemax, the centre you buy the decking boards from should also have information for you. Decking is more difficult to lay the closer to the ground you lay it. If it's way up, like 2 ft from the ground, you have ample room for foundation posts and trusses, then smaller joists, then the decking. In closer spaces, you have to get your measurements right and plan around the space restrictions. Ask the decking supplier for what they recommend for the product they're selling - and if you're not sure, walk away and think about it again - maybe pato pavers would do the job better...

Sonnenblumen

Surely laying a deck close to the ground, ie 6" (150mm) above ground level is simple and strasightforward. Most would construct a floating frame using
4"x2" boards at 14" centres and cross bracing at 18"-24". The ground should be level, spray area to remove any green/grass/weed. Fitting a liner would be advisable but ensure it is a horticultural liner, ie, allows water to permeate but prevnts weed etc to develop. Usually the weight of the deck is more than sufficient to hold it in-situ. If in doubt, some short posts embedded in
12-18" of concrete in each corner will ensure necessary stability.

Using a plate compactor on soft ground is absolute waste of time. Ensure all timbers (sub-frame etc) are pressure treated.

Tony255

What I did for my ground level deck was firstly kill off the grass then build the foundation with standard blocks, sunk them into ground level was hard work but totally worth it. Then got the heavy duty weed membrane from any garden center and put it over foundation and cut out where the blocks were I then put some hardcore on top to keep the membrane in place.

Build the frame of the deck using standard 6X2's and the weight of the frame was enough to support itself so didnt need to fix it to anything.

Best of luck with it.

The Sweeper

Sonnenblumen wrote: »

Surely laying a deck close to the ground, ie 6" (150mm) above ground level is simple and strasightforward. Most would construct a floating frame using 4"x2" boards at 14" centres and cross bracing at 18"-24". .

Yeah you'd think wouldn't you. I'm looking into it a lot at the moment, but whatever materials and design we use here, raised decks are easier. Because of the differnet environmental issues (low rainfall), the timbers and decks here are treated and constructed to have a lifespan of 15 years before you'd have to carry out major repairs (e.g. replacing boards - up to then you just oil them every three years and they weather the climate happily).

Subsequently my suppliers are geared to that level of construction, and don't like decks that are six inches from the ground. I'm sure the extra expense of a raised deck is a big feature in that.

Joey the lips

I layed my decking over waterlogged grass. It was done in the hope of making the area look better. It has worked. However the water has traved a little wider but i dealt with this using water soakage plants

I layed my decking straight down on the grass so to speak. I did not remove any sods. My decking was 14 ft x 12 ft so what i done is bought 15 patio slabs used 7 split in 2 of them to lay the decking on and broke the rest into sizable lumps and put them dowm on the membrane which i had spread everywhere. I then layed the 4x4" battons down flat as a base on the slabs and built my decking on this.I doubled up on the membrane as I had so much.

2 years on I have had no problems bar the fact the water traveld a bit. The decking still looks well. Has weathered a bit but honestly has not sank in the slightest. Feel free to be critical of what i done perhaps it will avoid more problems but as yet 2 summers down the line and heading into winter i have no problems.

liamolaighin

Id put down plastic over the grass area and save myself the hassle of digging it up. Weigh it down with anything you want. I'd personally put in small pile foundation under each corner post or weight bearing post to make entire structure more solid. Have a DPC between concrete and timber posts. Build away from there.