Thursday, August 3, 2017

Should I Waterproof My Addition?

I had a question/comment on a post I wrote about waterproofing, the person had an addition built to an older home and the contractor recommended that they tar and dimple board the foundation to waterproof it. After reading one of my posts about what the proper waterproofing is and what is simply damp proofing they had decided that since I stated that tar and dimple board was not waterproofing but it was actually damp proofing then they shouldn't bother installing it on the new addition or anything at all.

Also the existing home foundation does not have any kind of waterproofing or damp proofing so they decided that there really wasn't a need for it in the new addition, as the old part of the home could flood easier so what was the point.

Now the thinking makes some sense when you think about it, that the existing house doesn't have any protection so why bother with the new addition because they are all connected as one so what's the difference right? Wrong.

Just because the existing house doesn't have any protection is not an excuse to be cheap and not try and protect the new foundation.

Let me clarify a couple of things about what I was talking about when I said that tar and dimple board wasn't waterproofing;


  1. Tar and dimpleboard is not waterproofing it is considered "damp proofing"
  2. T & D does stop moisture from penetrating the concrete foundation.
  3. T & D will eventually dry out and fail, where other forms of "waterproofing" will not.
  4. T & D can be easily damaged from outside forces.
Tar and dimpleboard is far better then nothing, it is just the bargain basement version of water protection for your foundation, the cost for the proper waterproofing is worth it, but if it's between spending a little bit of money for tar and dimple board compared to NOTHING then please people buy the tar and dimple board!

Now your probably saving what's the point as the rest of the house doesn't have waterproofing;

Well you should dig up around the whole house and properly waterproof the existing foundation to match the new addition foundation this will guarantee that you have little to no issues in the future.

If that's not in the budget then you need to protect the new addition as water penetrating a new foundation is not a good thing; 

  • Water saturating a new concrete wall will eventually cause damage over time. 
  • Once water has saturated the the concrete in a freeze the concrete can be damaged.
  • Mold can form inside the new foundation causing health problems.
  • Floor joist can be damaged from the moisture penetrating the foundation.
Modern additions with modern construction practices do not do well with water and moisture, they fail a lot faster then older construction.

So please, everyone at least do the minimum when it comes to protecting your foundation, this is not the place to try and save money.

Rob Abbott
Village Builders Inc.

No comments:

Post a Comment