[Terre]

I have a client requesting paver bricks to replace her drive, sidewalk, and front step. As many of you know, this is out of my league. I've had two subs come out and take a look at the project, and I'm getting totally different answers from them.

The issue is the home is built in an area where the developer has had to go back and repair major structural damage due to bentonite in the soil. This home has no structural damage, however the sidewalk and the step to the front door have parted company by about 3 inches.

The client thinks that paver bricks, set in sand, will 'float' and solve the issue of shifting soil. I have doubts. I've had two different subcontractors out, one says sand is fine, the other says the only way to go is mortared.

Suggestions?

[4seasons]

maybe call in an engineer to test soil
or
look at more subs.
because Denver ---- dontgo w/ the sub that said sand
sub that said concrete --if the base isn't done correctly then you'll have same problems.

[Stonehenge]

Bentonite is a clay that absorbs a fantastic amount of water, and is used to line large-scale ponds, because of it's ability to absorb water and expand (creating a nice seal for man-made bodies of water). If there's a lot of bentonite in that homeowner's area, and you are most certainly in a freeze-thaw zone, that would seem to be the worst possible soil situation you could have. If the soils are full of water and freeze - big movement. Then they thaw and dry out - big movement in the other direction.

If there has been structural damage and a developer has had to repair, odds are that there's been an engineering firm involved in this process. See if you can track down who that is and give them a call. You might be able to get some quality information on how to proceed for free.

If that fails, I'd take 4season's advice and have the client pay for a soils test, so you can determine your best course of action.

My gut reaction is that pavers on sand will not provide a long-lasting pavement. But I'm not an engineer.

[Terre]

Stonehenge hits the nail on the head, bentonite type soil, which most of Denver is built on, expands and contracts 35 to 50% on average. There have been innumerable lawsuits due to improper construction even to the point of million dollar homes being uninhabitable.

This year has been much wetter, after multiple years of drought. Landsaping becomes a real challenge. The recommended procedure, is not plant anything within 6 ft of the foundation, no water, not even drip systems, within 10 ft. So, most landscapers go with rock, and then I get the calls from homeowners who want to eliminate the rock. Touchy situation, and I tend to use a lot of xeriscape plants.

I think I'm going to back away from this one, and recommend she choose her own hardscape installer. Hopefully, I can retain the softscape portion of this job, but keep my ass out of hot water.

[Fine Edge]

So, if bentonite is so prevalent in the area, are paver walkways non-existent? If not, how are they holding up?

[dan deutekom]

Here's my 2 cents

Jeff has hit the nail on the head and the long and short of it is that there is no easy solution. In my mind I would over engineer your base for stone using cloth below your base and using lots of base. I don't doubt that it will move at some point. Your client is just going to have to realize that somewhere in the future the stone will have to be picked up and relayed. If the stone is mortared it will be much more difficult to rectify movement in the future (as well as looking a lot worse when it heaves) but if layed in sand it is easy repair job.

Be honest with your client and let them know what they will be facing in the future. I have found most clients are very understanding when you are honest with them and you end up with future work from them as well.

[tom]

Where in Denver is the job located? I can definitely relate with the expansive soils. It's amazing what can happen to driveways, walks and patios.

Dan is right about being honest with your customer. Be up front and educate your client as much as possible about future problems.

It never hurts to involve an engineer if they are willing to pay for it, but it also never hurts to pass on something you aren't comfortable with.

[Terre]

Wow! Someone else from Denver! About time. Hi, Tom.

This particular job is in Highlands Ranch. Until I started doing some research, I was only aware of the SW metro area and 6th Ave West as being the bad areas. However, this is the second place I've run into issues with this.

I have no problem at all being up front with my customer, we have a pretty good rapport at this point. I'm just reluctant to recommend she go with a particular subcontractor or method when I don't know what I'm talking about. We're working on a three year landscape plan, and I intend for her to be happy with me for the entire time!

Yes, Fine Edge, there are pavers in use a lot of places in this area, but this soil issue is pretty wierd. One entire neighborhood in the southwest metro area is well known for being built on this stuff, some homes have had major repair, while the house next door is perfectly fine after 20 years. My daughter was renting one of those homes, and moved after hearing a loud noise and watching a new crack appear across the entire ceiling of the master bedroom. It was large enough to put her finger in.

I"ve broached the subject of an engineer, but she isn't really receptive. She isn't from this area, and since her home has never had issues, while others in the area have, she mistakenly seems to think her home is safe.

I'm going to have to be extremely cautious with drainage, and be sure that what gets planted close to the foundation doesn't require much water. The pergola, and waterfall aren't a problem so maybe I can get her to focus on those first. If I can postpone the paver problem to the 3rd year, I might be smarter by then.