Retaining Wall Backfill

For a terraced look in the backyard or for claiming more land if you are living on a slope a well-constructed retaining wall can add more living and growing space. Theses are basically “earth dams” which need a strong support to hold back the dirt.

In the past many of these used to fail after years because most of them used to be made of wood. ven pressure-treated wood only has a limited lifespan in normal soil conditions. However, cement was no better because it would crack in a freeze-thaw situation in wetter climates.

The new cinder-block- or pressurized concrete block- systems work better because each block can move with expansion and contraction. There is no cracking or falling over. This is in part to do with the wall being angled back. This means that a 1″ lip on the top front of the block pushes the next course back so if the blocks are 10″ high then for a 60″ height the wall angles back 6″.

A big part of a retaining wall system is the material directly behind the wall. Since water also causes a lot of pressure against a retaining wall there has to be a way to get it out before the pressure becomes too great. Before the wall is built a 4″ perforated pipe should be put down on the bank side and this should drain water away so should be slightly angles lower.

The next step is to get 1″ crushed rock behind the wall to aid in the drainage. So the wall should not be built directly into the bank but should have a space behind for the drainage rock. However, this buffer can get clogged from the dirt behind as the silt seeps in with the water. So landscapers use a fabric to strain the water and keep the silt back. This is spread over the bank before the crushed rock is put in against the wall itself. if you want a flower bed on top of the wall then the fabric can be put down between the rock and the topsoil.

For walls over 6′ usually 2 walls are built, the top one one staggered behind the first one.

Gutters and Drainage – Keys to Ending Wet Basements

Most of us have seen the dark water stains on a cement basement wall or the puddle on the basement floor and wondered how the water got there. Well, besides being strong and a solid foundation cement is very porous and water can seep through. This is why most new homes are tarred or wrapped with a waterproof membrane to prevent this. However, unless the floor pad has vapor seal underneath water can still up though the seams between the surface and the wall.

Gutters: One of the best ways to prevent a humid basement is to stop the water before it gets against the foundation. This begins at roof level with gutters which can accept the amount of water draining off the roof. A small amount of rain on a large roof can produce dozens of gallons of water in a short time so its best to have a gutter system that can handle this.

Downspout: Another important part of the system is the downspout. As the name implies downspouts take the water from the gutter to ground level. However, if the gutter is overflowing there is a good possibility that there are not enough downspouts to carry this away. Adding one more in a critical spot will enhance the drainage.

Drainage: When the water gets down to ground level it needs to be immediately directed away from the foundation. If the home is on a hill this is easy because the water will run away but if it is not then you have to make a path. Digging a 2′ X 2′ corridor around the foundation and putting in a 4″ perforated pipe will do a lot to take the water away. The downspouts can go directly into this pipe and the exit for this trench should be angled downward slightly to give the water an easy path away. Then the trench should be then filled with 1″ gravel or crushed rock.

This gets the water away from the foundation rather than sitting and allowed to seep. But you have to have good gutters to get the water where you want it before you can direct it away..