[EpicInterlock]

Jeff,

I'd like to see a picture of the geo grid, because I'm not sure if we're using the same terminology (Canada vs US).

I like the idea of tying into the foundation using a cement slab, but like Raj says, in Canada, digging 4' just isn't practical. I would have to charge accordingly, which would mean my success rate for getting jobs dropping dramatically. The geogrid should be a much better option, and I would definitely start using that option.

Anyone else have similar experiences with settling around foundations, especially driveways? Any other suggestions other than repairs?

[AZTLANLC]

Ok honestly I don't really know how to deal with this problem but how about this option, for a 7' by 7' landing drill 2 9" holes all the way down to the foundation footings and fill with concrete I'd say a foot away from foundation and spaced 4' then build a reinforced 4" concrete pad extending to virgin soil or drill another 2 holes
Hope I was able to explain things.

[cutntrim]

I think Paul has mentioned before about mixing Portland into the base when compacting on certain jobs.

[dan deutekom]

I am going to throw a monkey wrench into all of this. When I do work at new construction I tell the client that there might be some settling. I warranty my work for 5 years and I will go back and fix things if it settles. I do my best to pack the base, and I will probably end up going back to about 2 out of the 10 jobs that are done on new construction. Most of the jobs that need to be fixed usually take a couple of hours to fix. All of the cutting and measuring are already done so it is just a matter of dismantling adding some more base and relaying in a localized area near the foundation. I build it into my price and I save a whole lot of work on 8 out of 10 jobs. Also it has given me all sorts of repeat work because I am honest with the client, I always check the jobs in spring to check for settling and fix them without the client calling me. When I go back to check the job you get to talk to the client about future projects and when you fix something without them even asking they know that you stand by your product and they tell everyone they know.

[Stonehenge]

Originally posted by EpicInterlock
Jeff,

I'd like to see a picture of the geo grid, because I'm not sure if we're using the same terminology (Canada vs US).

I ran a Google search for Versa-grid, and it looks like they have a new "1.5" that looks more like some of the other geogrids out there (mirafi, strata, etc).

The stuff I'm talking about looks a lot like silt fence. But bigger. And stronger.

[Stonehenge]

Dan, I'm wondering what kind of adhesive you use, because with the stuff we use (SRW), everything you take apart has to be replaced, because the adhesive takes chunks of the material it's holding together with it when it comes off. So we have recut everything.

[dan deutekom]

I mostly use Paverbond that Unilock supplies. If I take a spade and put it between the stones and give a slow easy pry it just slowly breaks free. It's kind of like taking something apart that was glued together with rubber cement. It stays rubbery even after 5 or 6 years. I just scrape off the old adhesive and if it is really stubborn I might use a propane torch to get it off. I can't remember ever breaking a block taking it apart. When I relay things it just goes back together like original.

[PSUscaper]

On the issue of pinning a structure to a house. In my area at least, the code states that anything attached to the house needs a footing. Once you pin it to the house, it is now attached, and needs a footing. Also, the thought of 3-6 tons pinned to the foundation seems a little scary. If the subgrade does settle, you know have the load of the entire structure on those pins, and on that foundation. I'm not too keen on a wall being able to support that kind of stress. I think you can use the pin method, but then have to at least put a footing on the front of the structure. I've seen this method used by a few masons. Just think of the the leverage being put on those pins if the front of the stoop starts to sink. That is a lot of weight being multiplied, especially if it is a long set of steps.

Bottom line here is, as I've mentioned before, is we are basically designing economically here. By using SRW blocks, we are accepting the fact that we don't need a footing and can save the client money. If settling occurs, well....that is the price you pay for saving a few bucks on the intial installation.

If you don't want settling near a house for stairs, dig down to virgin soil and put the footing in. That's all that can be said. I loved the other day when Stone mentioned what he tells his guys when they screw something up.....something along the lines of 'imagine the hardest, biggest pain in the but to fix it, and do it that way!" This is the same situation.

As for walkways and brick work settling near a foundation, I'm with Dan somewhat. If it does settle, go back and fix it. It is going to happen, and again, the economics of doing it the first time so it doesn't settle often far outweigh the cost of just going back and repairing the few jobs where it does.

One last thing....lol, have to do it because how can I not.

Matt, one quick note. 2 years in not a lot of time, and 15 isn't either. If you want to prove yourself here, I'll ask a simple question.

On a job where you are going to have tons of heavy equipment rolling in and out of the driveway, do you:

A. Install a paver driveway apron at the beginning of the job so truck after truck, machine after machine, can roll across it?

B. Install a paver driveway apron at the end of the job, so that less heavy traffic runs across it?

Every one here can answer the question first, then Matt can.

We'll see what 2 years and what 15 years of experience amount too.

[mrusk]

Originally posted by PSUscaper
On the issue of pinning a structure to a house. In my area at least, the code states that anything attached to the house needs a footing. Once you pin it to the house, it is now attached, and needs a footing. Also, the thought of 3-6 tons pinned to the foundation seems a little scary. If the subgrade does settle, you know have the load of the entire structure on those pins, and on that foundation. I'm not too keen on a wall being able to support that kind of stress. I think you can use the pin method, but then have to at least put a footing on the front of the structure. I've seen this method used by a few masons. Just think of the the leverage being put on those pins if the front of the stoop starts to sink. That is a lot of weight being multiplied, especially if it is a long set of steps.

Bottom line here is, as I've mentioned before, is we are basically designing economically here. By using SRW blocks, we are accepting the fact that we don't need a footing and can save the client money. If settling occurs, well....that is the price you pay for saving a few bucks on the intial installation.

If you don't want settling near a house for stairs, dig down to virgin soil and put the footing in. That's all that can be said. I loved the other day when Stone mentioned what he tells his guys when they screw something up.....something along the lines of 'imagine the hardest, biggest pain in the but to fix it, and do it that way!" This is the same situation.

As for walkways and brick work settling near a foundation, I'm with Dan somewhat. If it does settle, go back and fix it. It is going to happen, and again, the economics of doing it the first time so it doesn't settle often far outweigh the cost of just going back and repairing the few jobs where it does.

One last thing....lol, have to do it because how can I not.

Matt, one quick note. 2 years in not a lot of time, and 15 isn't either. If you want to prove yourself here, I'll ask a simple question.

On a job where you are going to have tons of heavy equipment rolling in and out of the driveway, do you:

A. Install a paver driveway apron at the beginning of the job so truck after truck, machine after machine, can roll across it?

B. Install a paver driveway apron at the end of the job, so that less heavy traffic runs across it?

Every one here can answer the question first, then Matt can.

We'll see what 2 years and what 15 years of experience amount too.

When there are change orders issued and the town hold you up on additional permits, and you have no 1 or 2 days jobs to go to, you have to do something to stay busy. I ran about 10 tandems truck loads, 2 concrete trucks, and a concrete pump truck over my paver apron and it has not moved a 1/6th of a inch. And why should it??? Its installed correctly.
Next year more trucks will be rain over it when the back yard gets done. I am not even worried about the loaded gunite trucks going over it.

If people are worried about running trucks over paver aprons, i'd question their installation methods.

Ideally, i would of done it last, but when the town puts me in a bind with permits, i need to do what i need to do to stay busy and to keep moving foward on the job.

I hate when people run their mouth when they do not know the whole story.

[Stonehenge]

PSU - Are concrete slabs tied to foundations in your area? Like driveways, sidewalks and such? They are almost always that way around here, and none have frost-free footings. So I'm wondering if that code may not apply in the situation, or if your code is excessively restrictive. And since I've seen driveway slabs tied to foundations, I'm not so worried about our steps (which are usually not that big).

@ mrusk - n/m

[PSUscaper]

I haven't come across many slabs tied to foundations since I started. And yes, codes are excessively restrictive in the area, not to say I run into many problems with them for 95% of the work I do.

Not to say it won't work, it just concerns me with the way you do it. I suppose the pins would bend, or pull out before they damage the foundation if settling were to occur. With most new homes having poured foundations rather than block, I just worry about what kind of damage could occur if the pressure were to pull on the wall. With block foundations, maybe only a few blocks would break at the point of attachment. With these new foundations, it seems possible to cause damage along the entire wall as they are one giant unit. Also, with poured foundations, they advise against drilling any holes, as it causes a weak point in the overall structure. Very similiar to truck frames, where they don't want you drilling holes into the frame as it can cause a week point. Not to say a few 1" is going to cause a problem, but I'm just concerned if they did and the liability tied to that.

"I hate when people run their mouth when they do not know the whole story".................no comment.

[Paul]

If done properly there is no problem with a cantilevered concrete pad attached to a concrete foundation. Concrete works best in compression, that is where it has it's strongest.

[PSUscaper]

Paul, I know you have the answer to this, so what does 'done properly' mean? Would not the initial concrete foudation have to have been designed and installed to fit this criteria in the first place? I believe it can be done, but before I go cantilevering a set of 3 ton stairs off of someone's foundation, need to know for sure it isn't going to cause structural damage. I would rather have the stairs sink than do that.

[Paul]

It depends on how big the entrance is really!

A small entrance (say 8' x 6') only needs a 6" thick slab at the wall 4" over the rest this allows the lower portion to act in compression holding up the pavers. Larger entrances would require an inset of re-bar and concrete piers like most stoops are made with. Most stoop footings don't even have any re-bar in them due to concrete acting in compression would distribute the weight over the wall for a greater area

One thing I would have to say is I would like to give the concrete a bit more time before would installing pavers and walls over it to allow it to come to it's rating (5000 psi) Any pins or bar drilled into the foundation wall 4" or less are not going to cause any problems figuring most steel bends with a lot less weight than a 5000 psi concrete wall would. The pins act as a shear allowing the concrete pad to remain in contact with the wall.

The thing to remember is compression, as long as it is spread over the entire area it works, if you tried to attach it to a single point you would then have big problems.

The best way to overcome the problem in the first place is to have lots of clear gravel dumped into the overdig before backfilling. I know this is not possible with every job but a $200 load of gravel sure is cheaper than all the other methods that I know of.

[johnkeegan]

Being that I'm not an engineer/architect, the idea of connecting a slab to a foundation that will be burdened with tons of block, makes me nervous. If the dirt under that slab settles (which we should assume it would) that seems as though it could create an unusual, concentrated,sideways prying force on the wall. Something that the original design of the house did not factor in.
Some here have concerns about using compacting equipment too close to a foundation. Surely this type of slab would create a greater and more contiuous force.
I wonder if this isn't one of those areas that you may want an engineer or architect to sign off first.
Also the geogrid ideas. Again, run this past an engineer (most suppliers have one on staff). The grid is designed to interlock soils to minimize shifting sideways, not to stop the up and down movement of a crushed stone pad.
.....As a side note, what's a little surprising about many of the comments here is that on one hand certain people are being attacked for their inexperience and overzealousness (which may be true) and yet many others are treading into areas that should probably be left to those with even more knowledge (in specific areas, such engineering) than those of us who have 20 or so years experience as "landscapers." Especially, if it involves damaging someone foundation. Sorry, I want an engineer's stamp and blueprint to cover my butt before I tie into a house.