Expert: Bruce E. Johnson - 9/6/2008

Question
QUESTION: I have a very experienced mason that wants to repair the mortar joints on my brick stairs by using caulking instead of repointing. A couple of other masons never mentioned anything about calking and they wanted to repoint the areas where the mortar is cracked or loose.  He said the caulk will hold up better to expansion and contraction since it looks like water is getting in there and causing hairline cracks to the brick.  I am concerned about the aesthetics of the job if he using caulking and don't understand why he can't just repoint the stairs especially since he mentioned using siloxane to seal the bricks afterwards.  Also, I have a 1 or 2 inch wide gap in the concrete walkway and he mentioned cutting out the gap and putting brick there to act as an accent and he said it will also act as an expansion joint.  I have no clue if this is correct.  Can you please help???  I live in the northeast.

ANSWER: Hi ali, repointing will give you the better look esthetically.  There are some mortar caulks out there now that accomplish both things caulking and pointing.  If the project is going to be treated for waterproofing already I would tend to agree with the masons that want to point it up.  But if it becomes an ongoing issue or has been and ongoing issue and pointing doesn't seem to be working then you may need to go the caulking route.  A good urethane caulk such as Vulcum or Eucolastic is recommended for cement expansion joint applications. hope this information helps feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com

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QUESTION: Hi Bruce  Thank you so much for the quick response.  However, I had a second part to my question.  There is a concrete walkway that has about a 1 or 2 inch wide gap and the mason came of with a creative idea of making the gap wide enough to put bricks spanning the width of the walkway where the crack is.  He said he would set the bricks in sand dust or sand stone dust and the brick would act as an expansion joint.  Does this sound plausible to you?

ANSWER: Hi ali, yes that is a good idea.  I just had a similar question a couple of days ago and made the same comment.  I hope this information helps feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com


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QUESTION: Hi Bruce  Just thought of one last question.  The mason wants to seal brick with solaxane after caulking or repointing.  If I choose the mason that caulks instead of repointing, can sealing with solane be done the same day or is there a curing time for the caulk?  Alternatively, if I choose the mason that wants to repoint instead of using the cauking, can sealant be used same day or must the mortar cure?

Answer
hi again ali, mortar can normally be sealed with siloxane based sealers after curing 3 days.  As far as the compatibility with caulking?  You might want to have him lay down a bead of the brand caulking he plans on using and let it cure for a day or two and then test it to see if it will react to the solvents in the sealer.  Without knowing exactly what type of caulking he is using I can't be sure if it will turn yellow or melt or what kind of reaction it will have to the other products. I hope this information helps feel free to write again regarding this or other matters, sincerely bruce e johnson..bejohnsonconsulting.com