By John Lam Asset Enhancement • Building Technology • • • 0 Comments

Protect your roofing membrane

When I was a boy, I saw the construction worker at roof heating up the Asphalt block with very bad odour smell. Bituminous asphalt were usually applied in liquid form in row by row with some over-lapping at even interval spacing. Although this materials are proven to be very weather resistance and durable once after curing and set, it is not encouraged to use in new works as per the General Specification (ASD) Clause 12.50. With the advancement of technology , there are now coming with various type of ready-applied roofing felt and some type are even in spraying form.

Nevertheless, the typical defects like blistering of membrane, sagging of membrane, incorrect surface water fall , poor outlet details , lack of backing rod for sealant in expansion, add-on structure impairing the roofing are still prevailing. These are attributed to the poor workmanship, lack of inspection and inadequate design details consideration. Indeed, even though the defects exists , it does not mean we have to end the life of roofing by complete re-roofing. A more sensible way is to carry regular inspection and maintenance than to leave the roof undue long time unattended.

 

By John Lam Building Technology • 0 Comments

Maintenance Problem from “Party Wall” in Urban area

According to the Land Surveyor “Word Press” 16, Aug 2012 “by Edmond Cheung,  “Party wall” is the physical separating wall of two adjoining building. It functions to divides houses of two different owners buildings but the wall is in shared ownership. In the DEVB(PL-CR) 2/15-08 dated 29th Mar 2010,

A party wall is an integral element, and it is unlikely that half of the same can be removed with the other half remaining intact. Therefore, the removal of the party wall is subject to heavy control stated in Buildings Ordinance Cap 123. To the very least, the lot looking for removal of his own part of “party wall” must have the consent from the rest of owners of the “party wall”. To ensure the integrity of remaining half , we usually apply the structural strengthening by in the steel bracing bolted and mounted to the structural element of the building.

This remains of party wall structure , i.e usually the half of its original wall, becomes some maintenance issues attributed to the already aged cement mortar in brick and rusting of the steel bracing by weather. The steel members sometimes become rusty and decomposed to have lost its strength and also becomes bittle . This also creates the problem of water seepage through the bolt hole path to the interior space. Owners also need to aware that the thickness of party wall is GFA consumable. Since the problem of maintenance is impairing much the integrity of wall and also poses the water seepage problem , it is important to pay attention to it maintenance and to carry out routine inspection.

The steel bracing is bolted to the structural frame of the RC building and this bracing to strengthen the integrity of the “party wall”