What are you doing about standing water on your roofs?

Do you know that just 25mm of standing water over an area of 10m2 adds a quarter of a tonne to the structural load!   Over time this will become exaggerated as the effect of the load will cause deflection of the structure.

Contemporary high performance waterproof systems provide significant improvements in the roofs performance and longevity with warranties of over 20 years not un-common.  However after refurbishment it is unlikely that the roof will be monitored for the effect of any additional imposed loadings cause by standing water.  Potentially jeopardizing the warranty.

It is also true that many retained roof sub-structures are classified as ‘Fragile’ under the HSE Guideline HSG33.  Who can calculate the long term effect on a super imposed load of a tonne of water every 40m2?

It is incumbent upon the Building Owner to ensure any roof refurbishment is signed off by the local Building Control Officer as part of the legislative Building Regulations : Part L regulations.   There is firm case history of projects not signed off as a direct result of concerns over the structural ability of the roof to withstand the super imposed load of standing water.

So what can be done?  The pragmatic solution can normally be found by specifying tapered insulation.  Insulation of course meets the first primary objective of the Part L regulations, but combine this with a bespoke tapered design which eliminates standing water on the roof and you have 2 solutions for the price of 1.   Good business, robust design!

At M&J Group we have in-house tapered insulation designers, so if we can be of assistance please do not hesitate to contact us.