Membrane under decking?

McNulty

Hi

Hoping someone could help with a query. I am planning to put down around 30 sq m of decking in the next few weeks. I've ordered the wood (Garapa hardwood) and the "underneath" timber from a building supplier. My query is that the deck will mostly be going over what is currently lawn. I want to keep the grass/weeds from growing back up. Do I need to go with a weed membrane or ordinary plastic? If it is membrane, is Plantex a good idea and does anyone know of a decent supplier in the Leinster region?

Thanks for the help!

Jim

the GALL

one of the main reason plants wont/cant grow under decking is if you remove the sun light (stop photosynthesis/plants cant produce chlorophyll/ cant breathe and die)so any membrane that stops sunlight will kill off plants but to aid this process kill off what you can first (weed killer etc etc) you may want to use a breatheable membrane which may help to dry under the decking so it doesn't turn into a swamp and may rot the deck supports if your deck support are set in concrete put a layer of stone in the bottom of each hole the will also aid drainage and to do a really good job treat all cut ends with a wood preserve (couprinol green/ white e this will stop any exposed timber for rotting in years to come:)

Sonnenblumen

Make sure the timbers you use for subframe are all pressure treated!

Important to use a breathable membrane, the Plantex liner depending on the particular grade quality has a lifespan ranging from 1-7 years. Mypex is a far superior liner (beware of cheap imitations) and has a life expectancy of 25 years.

For a neat finish use the nylon pegs for securing the membrane in situ.

stick-dan

First of all the quality of the membrane must be top notch because you are obviously not putting down the decking as an overnight job So i would go with Mypex or plantex, stay away from the cheap brands because they will degrade rapidly and just leave scraps of fabric underneath the decking. As for the timbers pre-treated they must be.Get the 8ft 4x4 pressure treated decking posts because if you were to treat them yourself it would not be enough. Then for preparing the ground that you will be working on, a day or a few before your construction of the decking area is to start scour the area with a strong weedkiller,e.g. HYTROL,SIMAZENE(think that is banned now not sure), weedol, or Round-up. Round-up would be the best as it is the more concentrated. Then you can do one of two things. you can lay your membrane straight down or you can scrape off the dead surface and then lay your membrane(although if you were to do this do it before the weedkiller application as to ensure maximum weedkilling in the earth.).

ircoha

I never use any of these membranes because they can act as a base for vermin,
I put down a base of Clause 804 Type A: it is both self draining and can also be used to support the deck.

I use galvanized RSJs which are leveled up and the deck framing for the most part is prefabricated on the lawn and dropped into place on top, the weight is more than sufficient to keep it stable
http://www.roadstone.ie/Products/Stone/Aggregates.htm

niceirishfella

You need a few rolls of TIRIM.
Get it from any hardware.