Waterproofing your new Addition

Waterproofing your new Addition

THE DOS AND DONTS

So, it’s that time of year. Brisk cold mornings, snow falling and ground freezing like concrete. Give it 3 months and one of the busiest crews about will be the waterproofing contractors. This will be due to the melting snow and ice, along with the frozen ground releasing moisture. This is going to lead to dampness and water seeping through basement walls causing all types of problems for homeowners and commercial units.

So, what are the solutions or better yet how do we prevent this expensive problems from happening? It sometimes baffles me why a weeping system is used internally. Does this not defeat the purpose of keeping water out? I would leave it as last resort it a gravity fed system is not viable.

From experience the issues must stop at the source. These are the two main things you need to look for when waterproofing your home.

1. Prevent rising damp
2. Create a barrier from exterior and interior wall

Preventing rising damp does not seem to be a big issue here in Canada. So many times, I have walked into a site where the contractor was happy to pour on top of mud or just some loose gravel. The water table could rise following rain which in turn would merit rising damp. This can cause mold and damage flooring which is laid on top of the concrete.

A simple solution is to install a DPM (Damp proof membrane) Usually depending on the grade we would spread some sand before laying it down. This would help avoid any sharp grading piercing through it.

See the figure below which will give you an understanding of home this is effective.

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Creating a barrier between the exterior and interior wall is not that difficult.

If the addition is in blockwork the procedure is as follows.

1. Install weeping system on exterior of footing
2. Parge exterior of blockwork – Make sure where the new wall meets existing structure is given more attention then other areas.
3. Tar over parge
4. Install dimple board which allows water run off at bottom
5. Always insure that footing is 8 inchs (1 block) below finish floor level. This is to allow water run off and stop any rising damp.

If you have any questions about waterproofing feel free to contact us at info@selfbuildcanada.ca.