We’ve had to assess structural integrity of two freestanding walls recently, the first was relatively straightforward and involved a resident who reversed their car into the boundary wall surrounding his apartment block. The client wanted to know whether the wall was safe in its damaged condition. Since it was also a retaining wall and damage fell outside of acceptable limits, we recommended that it was taken down and rebuilt. It was a very easy & objective decision based on information outlined in BRE Good Building Guide GBG 13.
The second was a little more unusual and called for a more urgent and subjective opinion. As a surveyor, there are often grey areas that call for professional opinion. In this particular case we noted damage to a 2m high rendered free standing wall, it had failed at its junction with the corner of the main building and also had a long horizontal crack at a bed joint. Both the leaning wall and the degree of cracking are easy issues to assess but what made this assessment unusual was the installation of a large zip slide to the rear garden that ended at the garden wall. The steel support post was installed just beyond the garden wall. In fact the damaged render tended to indicate that that users of this feature were hitting the wall hard with the base of their feet as the zip slide came to a stop. Now you might expect that hitting the wall would cause it to lean away from the zip slide but in fact it had the opposite effect. Impacting against the wall caused failure along a slip plane near the wall base, 4 courses up from the floor. Essentially, there was almost a complete horizontal fracture of the mortar bed joint. Impacting against the wall appears to have caused counter rotation at the top of the wall so that it leaned towards the zip slide button seat rather than away from it.