Question: I have an old Wolseley home, built in 1911, with a stone foundation that appears to be a limestone/Tyndall stone type. There are a couple of small areas that I am looking to repoint on the exterior above grade. It’s probably too small to be worth a contractor’s time, so I think this is something I could do. For this type of application, I was wondering what type of mortar do you use, as I assume that a Portland cement-based product would be too hard and may damage the stone itself? Do you use a hydraulic lime mortar, or is there a design mix that would be more appropriate?
Where could I source these materials in Winnipeg?
— Regards, Phil Slota
Answer: Choosing specific building material types for certain jobs requires technical knowledge that is beyond the scope of most home inspectors, unless they have specialized training or background in that area. For do-it-yourself advice, contacting a supplier that sells the particular products you require should be your best bet.
While I like to think I have personal knowledge about all things in homes, in many cases that is not reality. Home inspectors have varying backgrounds and come from many different previous areas of employment and expertise, but are rarely ever experts in all phases of house construction. The best inspectors almost always have a construction or design background, often as a specific trade, architectural technologist or engineer.
Those inspectors who have years of direct construction-related experience, particularly with houses and commercial buildings, will find it easier to understand building systems and explain issues related to those systems to their clients. As well, modern building science can be quite complex, especially in relation to building enclosures and air and moisture migration. Having some background in the sciences can also be a distinct advantage in doing this multi-faceted job.
My own background includes post-secondary education in the sciences, followed by more than 15 years in renovations and construction. This has provided me with a very good base to identify, evaluate and understand defects found in homes, but is not enough to continue to provide effective service for more than two decades.
An excellent home inspection training course was necessary for me to complete before starting out, but continuing education is also critical. Over the past 20 years, I have attended numerous seminars on all aspects related to building systems, health-related issues, building enclosures, defect recognition and other topics related to home inspections. Despite all this direct experience and education, there are numerous specific aspects of house construction and renovation that are beyond my scope of knowledge. Some of these are due to constant changes in building practices, but many are only understood by tradespeople in specific aspects of construction. Also, there is often more than one accepted practice or style for various jobs or systems, depending on the preference of the specialist involved. So, it would be impossible to keep up on all facets of modern home construction.
You have identified one area, masonry repair, which may easily fall into the category of "beyond the scope of the inspector." Unless you find a home inspector that was trained in masonry application or is a Red Seal mason, it is doubtful your question could be answered.
Even though the information may be available through research on the internet, or well illustrated in a YouTube video, it may not be reliable. It is hard to know who to trust when specific aspects, which may even be trade secrets, are desired. While I empathize with your dilemma, I can only give general advice rather than a specific answer to your question, in this case.
I am skeptical that you would cause any serious damage to your stone foundation, even if you used the wrong type of mortar. But I admire your desire to do the repairs properly.
Since the stone in the foundation has lasted more than a century, likely with several repointing repairs of the mortar joints at the exterior above grade, I doubt you could do that much harm if you used the wrong type of material. Nevertheless, the answer to your questions may be quite simple to obtain.
I would recommend contacting a local masonry supply company that services the wholesale industry and sells directly to the trades. They would likely supply bricks, stone, tile, concrete and cement mixes, and other masonry tools and supplies. Most companies of this type now have a website and retail sales counter, as well as one to service the industry professionals. They would certainly have sales staff that would easily be able to provide the proper advice and products necessary for you to repair your small areas of foundation mortar.
Asking a home inspector, like myself, for advice on the exact composition of materials for various home repairs may yield poor results, unless they had direct experience in that area of expertise.
Unless you are prepared to find and hire a professional mason interested in your small job, contacting a supplier that provides the materials that mason would use should give you all the answers you desire.
Ari Marantz is the owner of Trained Eye Home Inspection Ltd. and the past president of the Canadian Association of Home & Property Inspectors — Manitoba (cahpi.mb.ca). Questions can be emailed to the address below. Ari can be reached at 204-291-5358 or check out his website at trainedeye.ca.
trainedeye@iname.com
