What is Weep Hole in Retaining Wall?

In engineering, a weep hole is used to relieve hydrostatic pressure also known as water pressure on walls.

This decreases thickness and reinforcing requirements, hence lowering the structural design demand for the water and earth pressure.

Weep holes also lessen the structure’s buoyancy and uplift enabling the construction of lighter structures free from stability problems caused by uplift.

What is Weep Hole in Retaining Wall?

Weep holes are installed in masonry walls, retaining walls, underpasses, wing walls, and other ground-draining structures.

It offers a drainage outlet that enables any moisture that may enter the wall from behind through penetrating, capillary action, or leakage.

The installation of weep holes in brick masonry also acts as a ventilator allowing air to reach the back of the wall to prevent the growth of mould, dry rot, and dampness that shorten the life and performance of the structure.

Purpose of Weep Hole Retaining Wall:

A weep hole is necessary if you’re building a retaining wall below the water table since there will be too much water pressure on the wall.
Weep holes placed at the base of these buildings can help to lessen the added hydrostatic pressure.
The retaining wall’s base is located near the weep holes that avoid excessive pressure from impairing the retaining wall’s structure,”
Construction cannot have water built up behind the wall if it is built close to the water table.

Types of Weep Holes in Retaining Wall:

1. Open Head Joint Weep Holes:

These weep holes are created by removing mortar from the vertical brick joint.

The dimension of these walls matches that of the average joint spacing.

The standard distance between Open Hands Joints is 21 inches.

To prevent rain from entering the holes and insert from entering the hollow, a plastic weeps baffled structure is also used.

To help with drainage, a drip is included at the front lip.

2. Cotton Rope Wicking Weep Holes:

A rope up to 12 inches long is used to create these types of weep holes.

The opposite end is extended up to the cavity wall after being inserted into the joints.

The cotton absorbs the water from the wall’s back and evaporates it on the opposite side.

This process takes longer than standard weep holes.

3. Tubes Weep Holes:

Hollow metal or plastic tubes are used to create weep holes in tubes.

They are roughly sixteen inches apart.

To allow water to exit, these tubes are positioned at a small angle.

Make sure the angle is not excessively steep or flat.

4. Corrugated Channel Weep Holes:

Corrugated Channel Weep Hole in Retaining Wall

These weep holes aid in the fast drainage of water from the various pathways.

It is affixed to the mortar’s bed joint’s bottom side.

How to Drill Weep Holes in Walls?

Locate the wall that needs weep holes.
Using a measuring tape, begin measuring from one end of that wall until 24 inches are reached.
Now, mark the location with a crayon and measure upwards of 6 inches from the ground using the measuring tape.
After that, look at the location where both points meet and where you should install your first weep hole once it has been discovered.
Measure 60 inches from end to end of the wall and 6 inches from the ground to find the remaining weep holes using the same method.
Start by deciding on a location for the weep holes.
Place a mounting plate for a coring tool against the wall face.
After that, line up the plate’s centre with the hole’s proposed location.
Once the outer edges of the bolt slots have been marked on the retaining wall at each position, set the plate aside.
Then, using a half-inch carbide drill bit, set up a power drill.
Install holes that are two inches deep once the drill has been set to function.
Take the expanding anchor, and place one-half by two inches of it into each hole that was just drilled.
Make sure the anchors are secured by tapping them with a hammer.
To widen the wall anchors and tighten the bolts, use an adjustable wrench.
A three-and-a-half-inch coring bit must be fitted into a chuck that is located on the coring tool.
Set the scoring tool on the mounting plate that you have taken.
After affixing, tighten it using nuts to keep it in place.
The retaining wall’s face must be used while coring the hole.
Use clean water to wet the coring bit if the retaining wall is made of concrete.
Your first weep hole is finished.
To ensure that every weep hole is by the first one, repeat the process.

Advantages of Weep Holes in Retaining Wall:

Make sure the water that has accumulated on the retaining wall can drain.
Eliminate the hydrostatic pressure caused by the water logging.
Avoid damage and moisture.
It provides ventilation for the inside wall hollow, which aids in moisture control.

Disadvantages of Weep Holes in Retaining Wall:

When holes are drilled into the brick brickwork. The mortar leaks between the successive brick courses and falls into the weep holes. This may cause rubbish mortar to completely or partially block weep holes.
Pests like insects and rats can get access through weep holes.
There are several entry points into the interior of the structure including downlights, ventilator fans, and apertures for electrical and plumbing needs.
Weep holes might not offer the necessary airflow to adequately ventilate the internal brick wall in order to avoid the aforementioned issues with bug entrance and rubbish mortar or to make the weep holes more aesthetically acceptable.

FAQ- Weep Hole Retaining Wall:

Q1. Where should weep holes be installed in a retaining wall?

Retaining wall bases are designed with weep holes to let excess moisture that accumulates behind the wall escape.

Pore pressure arises as a result of the rising water table that increases the hydrostatic pressure on the wall.

In order to stop the development of too much lateral pressure, weep holes are provided.

Q2. What is the ideal distance between weep holes in a retaining wall?

Depending on the amount of water build-up and seepage, weep holes can be placed every 4 to 8 feet on an outside retaining wall.

Holes every eight feet would be sufficient if the wall is very short and the ground behind it doesn’t stay damp for very long after a rainstorm.

Q3. What occurs if weep holes are blocked?

Even some commercially available weep hole coverings, guards, and barriers have been built with ventilation holes that are too small.

Leaky Building Syndrome is brought about by these “solutions” that prevent air from entering the cavity, which can be exceedingly difficult and expensive to repair later.