Sealing the back of treated pine retaining wall

[Tubby2]

I'm just about to fix 100m or so of 200x50 treated pine sleepers and was wondering if there is any point of somehow sealing the back of the sleeper.

[Planned LScape]

You could use rolls of black plastic. I presume it is to seal it?

If the wall is higher than 400mm and it is retaining soil make sure you backfill right against it with aggregate, otherwise the weight of the waterlogged soil trapped against the wall may push it foreward. Drainage a good idea too, makes the wall triple in lifespan

[weisyboy]

y do u want to?

if you are going to put black plastis behind it it will require gravel and aggie pipe to drain the watter otherwise it will have a huge weight behind it.

[Tubby2]

y do u want to?

Just to make the wall last longer and prevent rot.

Was thinking of something like the black tar that gets painted on the bottom of telegraph poles before they get stuck in the ground.

[weisyboy]

the old telagraph poles were diped in creasote and sump oil not tar.

the treated pine is now garenteed to last 40 years. however do not use treated hardwood as it will for out verry quickly as the treatment only penatrates 5mm.

[Planned LScape]

a roll of plastic will last just as long and easier to put on too

Treated pine lasts a fair while in terms of rot, it's the warping that causes the dramas.