Level III – Advanced DSWA Certification

This test is in two parts which must be applied for and paid for separately. Candidates must hold a Level II / Intermediate certificate before applying for Level III /Advanced Certificate. Part A must be marked and passed before appling for Part B (Timed test – Retaining Wall).

Part A:

Candidates must build 54 square feet of curved wall plus an additional 54 square feet incorporating one of the features below. The wall must be at least 4 feet high. Part A is not a timed test, it is built on the candidates own time and therefore must be built to a very high standard. Previous test candidates estimate that it takes 100 to 120 hours to build both features (2 ½ to 3 weeks).

Test candidates must confirm that the test features are the unaided work of the candidate. The features will be marked by Examiners on the next test day. The candidate must pay the application and fee to the Stone Trust prior to beginning work on their features. The candidate must then submit at least 3 photos of each feature showing work in progress. The features must be completed at least 6 weeks prior to the next test day, at which time the features will be examined.

Part A is marked out of 40. Each feature must score at least a 13.5 for a total of 27.
It is common for one of the features to pass and the other to fail. If this happens Part A must be reapplied for in full. However the feature that passed does not necessarily need to be rebuilt, though it will be re-examined.

The 2nd feature must be one of these three options:

1) 54 square feet of high wall
2) 54 square feet of wall incorporating a lunky
3) 54 square feet of wall on ground with a slope of 20 degrees or more

Specs for Curve wall:

• Very smooth even curve to the wall on both sides
• Smooth even batter on both sides (the batter must be the same on both sides)
• A common mistake is for the wall to bulge above throughstones
• Very tightly built wall with very few wide joints
• Cope stone must fit tightly around curve

Specs for the Lunkie:

• The minimum hole size is 20” x 20”
• The wall ends that form the sides must be very well tied back.
• At least one through stone (tie stone) is needed on each side of the lunkie hole.
• The size of the lunky is not subtracted from the square footage of the wall.
• The lintel may not protrude
• Lintels must be strong, sit well, and have good bearing area on the supporting stones

Specs for the High wall:

• The minimum height is 6’ to the top of the copes
• Must include at least two courses of throughstones
• 1:8 batter is recommended, base width of wall must allow for this
• Even batter achieved on both sides
• Excellent line and straightness in needed

Specs for the 20-degree sloped wall:

• Stones and courses must be set level
• Foundation stone must be stepped and entirely below ground surface
• Through stones must all be an equal height above the ground
• No running joints
• Cope stones generally should be set vertically

Click Here for Upcoming Test Dates and Registration

Part B

Once a candidate has successfully passed Part A they can then move on to Part B which is a timed test building a retaining wall. Part B must be taken within one year of passing Part A or the candidate will have to re-apply from the beginning. If a candidate fails Part A, they must re-apply for this section, submitting the relevant fee each time, before moving on to Part B.

Part B consists of stripping down and rebuilding 49 square feet of retaining wall (measured on the face) in a 7-hour time period under the presence of examiners. The wall must be at least 4 feet high to the bottom of the copes, and should retain backfill to the bottom of the copes. The wall must be built straight without bulges or hollows. The Stone Trust Center currently has test stints for this level. Both sections are outside and tests are rain or shine events, so candidates should prepare accordingly.

Part B is scored out of 90 with 60 being the minimum passing score. Each section of the wall must also meet a minimum mark to pass. If a candidate fails Part B, there is no restriction on the number of times they could reapply for this section within the year since passing Part A, providing the relevant fee is submitted with each application.

Images of tests:

Below are images of several tests, some passing and some not, as noted. The first 3 images are Jared Flynn’s passing Part A test features.

A very well built level 3 part A curve wall. The wall end at the left is not part of the test. This wall passed easily — A very well built Level III Part A curved wall. The wall end at the left is not part of the test.
This wall passed easily.

A very well built level 3 part A lunkie. This wall passed easily — A very well built Level III Part A lunkie. This wall passed easily.

The combined level 3 test part A wall. Click here for the mark sheet for this wall (three images above) — The combined Level III Part A test wall. Click Here for the mark sheet for this wall (three images above)

The next three images are Brian Post’s first attempt at Part A. This test wall did not pass as detailed in the captions.

Despite being quite well built this curve did not pass. The primary reason for the failing marks was that the batter was unequal on the inside and outside of the curve. The steeper batter on the inside of the curve resulted in the top of the wall being about 1" off center from the foundation. The examiners also felt that the throughstones were too far apart (3' apart on the inside of the curve ment that they were almost 5' apart on the outside, which was too far). The hearting was also not tightenough, there were a number of places light was visible through the wall in a number of places, particularly under the coverband and under 2 of the throughstones. There were some minor bulges and hollows on both faces of the wall for which points were taken off, and the examiners were also looking for each cope stone to have perfectly even height, not mearly averaging the same height. — Despite being quite well built this curve did not pass. The primary reason for the failing marks was that the batter was unequal on the inside and outside of the curve. The steeper batter on the inside of the curve resulted in the top of the wall being about 1″ off center from the foundation. The examiners also felt that the throughstones were too far apart (3′ apart on the inside of the curve meant they were almost 5′ apart on the outside, which was too far). The hearting was also not tight enough, light was visible through the wall in a number of places, particularly under the coverband and under 2 of the throughstones. There were some minor bulges and hollows on both faces of the wall for which points were taken off, and the examiners were also looking for each cope stone to have perfectly even height, not averaging the same height.

This lunkie did pass but not by much. The bottom stones at the sides of the lunkie should have been longer to better tie the sides of the lunkie into the wall. The contact between some of the stones were also not the best and hearthing and copes could have used some improvement. — This lunkie did pass but not by much. The bottom stones at the sides of the lunkie should have been longer to better tie the sides of the lunkie into the wall. The contact between some of the stones were also not the best and hearting and copes could have used some improvement.

Brian's overall first pass at the level 3 part A test. The curve failed, the lunkie, passed, but an overall failure do to the curve. — Brian’s overall first attempt at the Level III Part A test. The curve failed, the lunkie, passed, but an overall failure due to the curve.

The next 3 photos show Brian Post’s second successful attempt at the Level III Part A test, about 6 months later. Brian rebuilt the curve and the entire coverband and cope, but did not rebuild the lunkie as that had passed. The lunkie did have to be re-examined, but since it had passed there was no reason to rebuild it.