[Andyboy]

Hi,
I am designing a flagstone path with mortared joints but I have a few questions regarding installation. Let me say that I am just designing it I will hire an installer but I am asking questions so I know how to spec materials and construction methods.

We are in a cold climate with freeze thaw cycles so I am aware of the risk of joints popping etc. but there are many examples of these paths around so I know it can be done. I would like to use limestone (probably Owen Sound or Similar) I am specing a 4" concrete base with wire mesh reinforcement but do I cut expansion joints into the base? How about the top? Also, what type of mortar do I use to set the stone and to fill the joints? Regular mortar that I am familiar with for brick walls has a limited holding capacity beyond 3/8" so how do you deal with 1-2" thick mortar base and 1" gaps in the stone. Actually, that is another good question - how wide should the joints be maximum?

Any advice would be much appreciated.

Thanks.
Andyboy

[ianc]

portland lime

[fakie99]

sounds like a reasonable installation method. no need for control joints on the slab; how would the break translate to the stone above it anway? i have always used type s mortar for the bed and joints, up to 2" joint (but ideally you'd keep them alot smaller.)

[Andyboy]

Thanks for the reassurance. As far as ensuring a proper installation are there any things I should watch out for or make sure happen properly. I will look into type S mortar and Portland lime.

Thanks

[jshilan]

Hey Andyboy I'm not sure how to notate it but the size or range of the pieces should be discussed and monitored. You don't want too many "small" pieces or oversized pieces. Also what happens many times with stone is that the walkway starts out one way and ends another (you see this when houses are veneered too). What I mean is that more larger stones are used in the beginning and more smaller pieces at the end. The walkway needs to be consistent in sizing and pattern. Also, should the installer "cut or chip" the piece to fit or use them as is? As mentioned by fakie earlier, you want an acceptable range in joint sizing (ie 1/2"-2"). Then there is the thickness of the stone itself. Usually an 1"+/- is fine in a wet laid application. Thicker pieces just make the work harder for the insaller and do not add much value. You can also require that they mix the stone from each pallet if the material is palletized (just in case the stone is from different sources). If you are really concerned/worried you can have the installer lay out the pattern on the slab prior to the install and then require them to have you sign off so that they can install it. This can be in the spec's or on the plan. It is a good idea, and protects you and the installer, althought the installer will think you're a PITA.

If this is new for you, try to steer the client towards someone with experience and not the low bidder. It will help you learn and save everyone a lot of aggravation. When the project is being installed try to be a "teammate" with the mason and not an adversary. Don't be afraid to ask the mason for help or advice either. Chances are they can help you as much as you can help them and ultimately give the client what you and they want and the contractor can make some money.