Waterproofing of Lamb House Bridge complete

We are delighted to report that the waterproofing work on Lamb House bridge was completed today. NDR produced a method statement for the works which was agreed with Dorset Bridges and followed meticulously.

The deck of the bridge was uncovered, thoroughly cleaned and then the surface was screeded ready for the application of the waterproof membrane. A bituminous primer was brushed on to the surface of the screed and the membrane laid from the ends of the arch to the crown with each layer overlapping the previous layer working towards the crown. Finally, a capping layer was laid across the centre overlapping both halves.

A lightweight waterproof flexible board was laid on the membrane as a protection against stone perforating the membrane. Type 1 stone was then laid on the board. The join between the parapet and the deck was waterproofed using strips of membrane overlapping the deck membrane and chased into the parapet.

Lightweight flexible waterproof material was laid along the edges to protect the waterproof membrane from perforation and type 1 stone laid over the surface of the bridge deck completing the waterproofing works.

The next step will be to compact the Type 1 stone where this is required and finally a sub layer of railway ballast will be laid so that track laying over the bridge can be carried out.