Retaining Wall Drainage
BRANZ recommends a minimum of 300mm of clean metal or gravel immediately behind the wall. We lay the first 150mm along the base, sit the perforated coil on top, then cover the coil with another 250mm of.
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Built strong. Built to last.
Engineered Retaining Walls in Lower Hutt
Top Retaining Walls Lower Hutt handles the retaining walls that come with paperwork. Anything holding back more than 1.5m of ground, and anything with a driveway, shed, pool or sloping fill above it, needs a chartered professional engineer and a building consent. Hutt City Council lists retaining walls over 1.5 metres in non rural zones as needing consent, and over 3 metres in a rural zone.
- We tell you at the first visit whether you need consent
- Chartered engineer design and producer statements arranged
- Consents lodged and inspections met through Hutt City Council
- Drainage on every wall300mm of metal, a drain coil and geotextile. Never an optional extra.
- H5 poles as standardThe right treatment for timber that lives in wet ground.
- Consents handledHutt City, Upper Hutt and Wellington, start to finish.
- Itemised quotesYou see what the drainage and the spoil actually cost.
Engineered Retaining Walls
Engineered Retaining Walls we build in Lower Hutt
Schedule 1 of the Building Act draws the line. A wall is exempt when it retains 1.5m or less and carries no surcharge, meaning no vehicles, no buildings and no extra load above it. Cross either condition and you need consent, however small the wall looks from the footpath.
Hutt City looks harder at two kinds of site. Steep hill sections through Maungaraki, Normandale, Korokoro and the eastern bays bring slope stability into the picture. The soft sediments through Petone and Seaview bring liquefaction into it. Neither means you cannot build, but both change the design and the timeline, and we tell you which one you are on at the first visit.
Retaining Wall Building Consent
Schedule 1 of the Building Act 2004 exempts a retaining wall when two things are both true. It retains no more than 1.5 metres depth of ground, and it does not support any surcharge or any load beyond the.
Read moreRetaining Wall Repairs
The most common by a distance is drainage. Water sits behind the wall, the soil gets heavy and the wall leans out a little more each winter. Second is rot, where the posts were never H5 or the drainage.
Read moreHillside Retaining Walls
People assume the exemption is about height. On a hill section it usually is not. Ground sloping up behind a wall imposes extra load on it, and that puts the job outside the Schedule 1 exemption whatever.
Read moreDriveway Retaining Walls
A retaining wall holds back soil. Add a driveway on top and it holds back soil plus whatever parks on it plus the dynamic load of a vehicle moving. A car is well over a tonne and a delivery truck is.
Read moreTiered Retaining Walls
The Schedule 1 exemption applies to a wall retaining 1.5m or less with no surcharge. Two 1.2m walls set far enough apart that neither loads the other are two exempt walls, not one 2.4m wall. MBIE guidance.
Read moreRetaining Wall Cost
These are national guide ranges for walls up to about 1.5m, installed with excavation, drainage and backfill included. The Wellington region sits at the firmer end of them, mostly because access here is.
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The part you never see
How we build a retaining wall that drains
Nearly every failed wall we get called to in the Hutt Valley failed the same way. Water sat behind it, the soil got heavy, and the wall leaned out a little more each winter. So we build the drainage first and the face second.
- At least 300mm of clean free draining metal sits behind the wall face
- A perforated drain coil runs the full length at the base
- Geotextile cloth wraps the top and back so silt cannot block it
- The coil discharges to daylight or to stormwater, never a dead end
Where we work
Engineered Retaining Walls across Lower Hutt and Wellington
We cover the whole Hutt Valley plus Upper Hutt and Wellington City.
Not sure which wall type suits your section?
We will come out, measure it and tell you straight. The site visit and the written quote are both free.