Totally new approach towards waterproofing compared to the present systems, it’s a Hybrid System compiling of all the previous concepts.
Proposed Roofing System shall Includethe Following Specific Stages:
The Combo Roofing system consists of multiple layers. Each layer has a distinguished purpose of its own and is thus mandatory for the 100% efficiency of the system. The following step – by – step segregated representation of the system with reference to the function of each layer.
The surface of strata to be waterproofed must be free from all kinds of oils &Chemicals. After making sure that the horizontal surfaces, edges& Corners are clean the skirting area is protected by using polythene sheet so as to keep it from being pitted by the jet of the sprayer.
The polyurethane foam is prepared by the mixing of polyol withisocyanate in the foam machine.This mixture is then sprayed onto the surface layer after layer until the desired thickness is obtained. A minimum setting period is maintained between the layers so as to get maximum bonding between them. It is very delicate process and requires skilledlabor.
The insulating properties of the foam can be compromised by moisture vapor. The coating needs to be able to protect the foam from a build-up of this vapor, so that it won’t reach the dew point. Anothermajor hindrance to the PU Foam is the U.V Rays from the sunlight. In Order to outgrow from these problems the following protective coating are provided.
The rubberized coating assists the foam at the time of expansion and contraction with respect to atmospheric temperature change and keeps it from damages due to elongation.
The separation layer acts as a semi barrier between the coating and screed, as direct contact to a rigid layer may reduce the elastomeric properties of the coating and lead to cracking.
This is the rigid protective course that keeps the underlying layers from direct exposure to atmospheric & limatic factors and also from direct loads that may occur due to overlying structures or any kind of possible traffic. It also helps in attaining the right amount of slopping for the roof. The Joint between the compartments are packed using Back –Up Rods and the voids are sealed using joint sealants thoroughly as these joints are one of the major points of weakness in the protection layer.
This is the final most layer applied to the system. It consists of liquid coating comprising of materials which safeguard the underlying layers from the harmful U.V Rays and heat Sun. This Layer is responsible for avoiding the cracking of the screed due to thermal expansions and contractions.
The corners created at the meeting point of the horizontal and vertical surfaces are always identified as weak –sports in water proofing. Water may seep downwards through these points. In order to avoid this weakness in the structure we make angle fillets. They also help in providing good runoff water flow on roofs. Apart from that it ensures that ne weak corners are formed during weather coating.
The joints lefts unattended after the removal of the top edges of the filler board are alsoaccounted as weak sports. They allow water seep ages as well as affect the integrity of the surface and the slopping. These joints are packed with spec cords and then the remaining space is sealed tight using joint sealants.it may done before or after the top coat as per the site specification.