Posted: Fri Mar 30, 2007 2:43 am
I recently had a contractor install a flagstone patio for me in the Washington DC area. The material used was random design of Pennsylvania flagstone mortared (#2 portland cement, I believe) to a poured concrete foundation. There is a sitting wall enclosing the patio that is made of Hopers Creek thin stone. It was all new construction that occurred during February when Washington experienced colder than normal temperatures. It was a battle to get the contractor to wait for temperatures above freezing to do the work. We have had some problems that I believe may be linked to both the cold weather and some attempts to cut corners towards the end of the job. Being a non-expert I am questioning what I am now being told by the contractor. Here are the issues that are troubling me and the contractors stated response:
Issue 1: There is a hollow sound on many of the flagstone pieces ranging from very small (few square inches) to very large (a few square feet) on the flooring when you knock on them. Most of the hollow pieces have already experienced at least minor cracking in the surrounding joints. My concerns are that dropping something on a stone will crack it and water build-up under the stones causing additional joint cracking until they come loose. Contractor response: This is normal and no need to worry. The joint mortar is what holds the flagstone pieces together, not the mortar bond from under the stone.
Issue 2: The cracking of the joints. Again, patio was completed in February. We have experienced significant shifts in temperatures since the patio was installed. I understand that some cracking can eventually be expected, but would not have expected this much this early. I believe the hollow sound has had some affect on the cracking experienced to date. Contractor response: Normal from expansion/contraction. Is this really the case?
Issue 3: Varying colors in joint mortar. My wife had requested a grayish color mortar be used so that the joints were not as pronounced. We wanted the stone to be the main feature. No color was added to the Portland/sand mixture and we liked the original color. However, the contractor has had to come back several times already to fix missed items that were both expected and not expected. In doing so, various batches of mortar were used in various parts of the patio to re-point, fill-in gaps, etc. We now have a rainbow of colors in our joints that are very unpleasing to the eye. Contractor response: The patio needs to be “acid washed�. What are the affects of acid washing? Will we lose the gray color and be stuck with a more tan color in the joints?
Issue 4: Cleaning up of excess mortar on retaining wall joints. Not only does the contractor want to do acid washing to make the color of the joints uniform, he wants to acid wash the stone sitting walls to rid them of excess mortar. The excess mortar is mortar that is either (1) rough, (2) has bled onto the stone from when wet, or (3) a patch-work of mortar from attempting to correct outstanding issues. Is acid washing really the silver bullet that the contractor has stated? Can all these items be corrected simply by an acid washing? Are there any ill effects to the stone from acid washing?
Any help you can offer would be greatly appreciated. It appears that the weather has finally broken here and I would really like to be able to start enjoying my new patio! Thanks.
Issue 1: There is a hollow sound on many of the flagstone pieces ranging from very small (few square inches) to very large (a few square feet) on the flooring when you knock on them. Most of the hollow pieces have already experienced at least minor cracking in the surrounding joints. My concerns are that dropping something on a stone will crack it and water build-up under the stones causing additional joint cracking until they come loose. Contractor response: This is normal and no need to worry. The joint mortar is what holds the flagstone pieces together, not the mortar bond from under the stone.
Issue 2: The cracking of the joints. Again, patio was completed in February. We have experienced significant shifts in temperatures since the patio was installed. I understand that some cracking can eventually be expected, but would not have expected this much this early. I believe the hollow sound has had some affect on the cracking experienced to date. Contractor response: Normal from expansion/contraction. Is this really the case?
Issue 3: Varying colors in joint mortar. My wife had requested a grayish color mortar be used so that the joints were not as pronounced. We wanted the stone to be the main feature. No color was added to the Portland/sand mixture and we liked the original color. However, the contractor has had to come back several times already to fix missed items that were both expected and not expected. In doing so, various batches of mortar were used in various parts of the patio to re-point, fill-in gaps, etc. We now have a rainbow of colors in our joints that are very unpleasing to the eye. Contractor response: The patio needs to be “acid washed�. What are the affects of acid washing? Will we lose the gray color and be stuck with a more tan color in the joints?
Issue 4: Cleaning up of excess mortar on retaining wall joints. Not only does the contractor want to do acid washing to make the color of the joints uniform, he wants to acid wash the stone sitting walls to rid them of excess mortar. The excess mortar is mortar that is either (1) rough, (2) has bled onto the stone from when wet, or (3) a patch-work of mortar from attempting to correct outstanding issues. Is acid washing really the silver bullet that the contractor has stated? Can all these items be corrected simply by an acid washing? Are there any ill effects to the stone from acid washing?
Any help you can offer would be greatly appreciated. It appears that the weather has finally broken here and I would really like to be able to start enjoying my new patio! Thanks.
