Deeper roots

Press, 22 July 1976, Page 19

Deeper roots

Last month Home Handyman ran an article on building a concrete block wait This was commended by the president of the New Zealand Concrete Masonry Association (Mr G. M. Jones), who was specially pleased at the use of metrics and the nationallyused block numbers. But there w’ere a couple of errors of omission in the article and one error in design to which Mr Jones has drawn attention. His letter reads in part:

“The wall as shown, being more than I.Bm high, would require a building permit.

“We are concerned at the structural stability of your wall design. Block fences, like timber fences, can attract considerable wind loadings and just as posts in timber fences need to be planted about 0.9 m (3ft) in the ground so similarly for block fences. The post holes as shown in your sketch should be perhaps 1.3 m deep with a spacing of say, 1.6 m to suit metric block modules.

“In your text the depth of foundation for a 6in

block wall is not given, except that it should ‘go down to clay.’ Again my association would recommend the use of post holes to ensure a satisfactory structural strength against lateral wind and earthquake loads. “The two major concrete masonry manufacturers in the area (Christchurch) are members of our association and will no doubt be able to supply further advice to any prospective home fence builders,” says Mr Jones.