Estimate this job (2 tiered wall)

[PAPS]

About to fax over a proposal for a (2) tier retaining wall for a client, and I wanted to see if my figure is in the ball park with the rest of your figures before i send it... I realize that many variable come into play that you cannot see on the job-sites, but I am just looking to compare numbers before I shock this guy with my number... note: We have all nec. equipment (bobcats, mini-ex) etc. There will be no renting of anything, or sub out anything.

1. 1st wall = 160 ft. by approx. 5 ft. height.
2. 2nd wall = 80 ft. by approx 5 ft. height.
3. Material to be used = Techo-bloc -CRETA
4. Misc. items: remove (18-20) 15' small white pine trees/stumps.
5. Misc. extra machine work = 8-10 hrs extra digging.
6. Re-topsoil damaged lawn areas = approx. 6 yards.


i think i covered all the basics... love to see if my price is in the same range as you's.... ;)

[creative concepts]

Just a few questions to better understand the scope of the job. Is there a stair well being installed for access to upper area behind the tiers? Do you need to do any soil stabilization with geogrid? How is the access for machinery? does drainage work need to be done( besides the usual behind the wall stuff)? Are you going to charge the client for the split pallet price?

Without this info and going on a general wall job with techo blocks I would probably price this job at around $55,000.00 depending on what you pay for techo blocks since they are very expensive up by me ( around $450-$500 per pallet)



Chris
Creative Concepts

[PAPS]

To answer a few of your questions:

1. No stairs to be installed...
2. No need for soil stabilization...
3. Very accessible (we will be able to get our Ex. + bobcat anywhere)
4. No additional drainage work nec.
5. i am not understanding this question? explain more??


- ur estimate is right on with mine.. Seems like a lot $55,000??? for a retaining wall I am thinking as i sit here... but he wants Techo-bloc which is really expensive, the wall is huge, and there is a ton of work.

[paul]

I have to question you on your building a two tier retaining wall with out renforcement. The rotational forces are much greater on a two tiered system than on a single wall.

We wouldn't build a retaining wall here over 4' high with out grid, and your building one 10' high with out grid??

I hope you have the wall desiged by a PE and he is letting you get away with it.

[PAPS]

i realize your concerns... and have thought it over and will be installing geogird on both systems to be safe. I figured with it being 5' we could probably get away with no grid... but its not worth it.. for a few hundred extra.. it should be done.

[paul]

The cost of the grid is so cheap :)

Bryan most people don't understand wall building, they think that 2 walls both under 4' or 5' the forces that work on them are minor, but tiered walls really are harder to build right than single walls. In the classes I teach explaining to landscapers that tiering is a harder build sometimes goes over their heads. You really have two walls that can rotate at the toe, the higher wall places forces at 45o to the bottom wall.

Now for pricing your wall, here walls run on averages from $24 to $35 per sq ft. So with out seeing your layout and not knowing how far apart the walls are I'll stick with the average here of $28 per sq ft. so figure $33K to $36K for the job.

Being it's only 1200 sq ft wall and you have access to the top and bottom of it plus room for storage of material and have little on no spoil removel. Also I'm figureing that your soils are good and you don't have problems with ground water or surface water.

[Stonehenge]

What Paul said.

And $25-35K.

[PAPS]

thanks for the quote... I am actually sending him a proposal for $31,500 for the Creta block ( I took a little off the price due to the fact that its so easy to work around the area). Should I break that down into materials and labor...???

Materials = X dollars
Labor = X dollar

I just want the guy to realize that the stone he picked is really expensive... what u think?

[landman]

PAPS

I'm NJ and my figure comes in at $44,500.00 $35.00 sq ft, geogrid, and extras you mentioned.

[PAPS]

Well.. i am going to give him a lower price because I think there will be a lot of future work at this site too. The site is so easy to work at for one, Also, the 1200 sq. ft is a probably slightly high estimate... the walls will taper down at the ends.. so that sq. ft is probably more around 900-1000. I have ran these numbers over and over and I feel that my 31,500 number is pretty good.

[steveair]

hello,

in general, most guys I know are pricing techo-blok at a base of 27 a foot, but for smaller jobs, like to be in the 30 a foot range.

Maybe I missed it, but I still don't see a answer to paul's question of whether or not you got a engineer to look at this project.

Not for nothing, but building a wall OVER 4 ft without a design can lead to SERIOUS, and I mean SERIOUS problems. Not just structurualy, but code wise.

I have seen/heard/experienced nightmare stories where inspectors will come in, measure the wall, and if it is even a hair over 4 ft, start asking a LOT of questions. I've seen 14 ft walls completely torn down so that the inspector can see proof of the proper installation of geogrid.

I know a few guys who use to sound just like you on the subject of needing a engineer or not worrying about the wall being over 4 ft. Well, after the first run in with a building code inspector, they all have changed there philosophies on building walls.

Also, I've seen '5 ft walls' where the buider 'thought' reinforcement wasn't needed collapse. I've also seen walls where the the installer 'thought' he'd throw some geogrid in as a safety measure anyways fail miserably.

Without the engineers drawing, you are putting yourself at great risk. For less than a 1k, you could have a drawing done. Is 1k saved on a 33k job worth the risk?

Granted, the wall may be fine, and you may feel confident, but it is a risk.

Also, in my own opinions, techo blok is a product that I feel is not as strong as other manufactures (its designed more for aesthetics than function). Block size is much smaller than that of others such as versa, keystone, allan, etc. I would be very nervous building a wall out of techo that tall without a stamped drawing. For something that tall, I would be thinking tumbled versa-lok may be better for strength and also more economical. Just my own opinions though:)

If anything, be sure to take pictures of your wall as it is being built. Be sure to take a few shots of the grid being installed (if you do install it) and be sure to put them in a safe place. They may save you but some day.

And, just a note. A 5 foot wall is not code. plain and simple. Do guys get away with it, yes, all the time.....but, a lot of guys also get caught.

steve

[PAPS]

Steveair... thanks for the heads up and the comments...
The client really likes the Techo-Creta, I told him that I thought that Keystone would be a better choice for this job. So, I gave him a quote for both products. The wall will be basically installed for looks. The area being retained is a slope in the woods... we could actually do a rockery with some planting and it would be nice too, but he wants some walls installed for looks. We are going to use geogrid without a doubt... at first I questioned it... but realized that its a neccesity. i will be contacting the town for local permits etc. before starting. If the town says i need an engineer... so be it.. i'll get an engineer. But i am confident that the walls will hold fine. We have done many walls, and to date, have had no problems with any of our work.

[steveair]

It sounds like you know what you are doing then!:)

I personally don't like the techo for bigger walls. That's why I really like the tumble versa-lok now, because its a nice compromise between the techo and a 'regular' wall block. Plus, they've re-engineering the tumble versa-lok now, so it is as structurally equivalent to the non-tumbled v-lok ( they use to actually tumble the wall block and this made it very unstable.....now, they have a process that basically only tumbles the face of the blocks, not ruining its structure. They basically just beat the hell out of the face with chains)

From my own experiences, the techo seems weak as the smaller pieces seem to be 'floating around' on the inside of the wall. I'm interesting in seeing some of the walls as the years go by and whether all those pieces will stay in place.

Techo is a beutiful block though, and once people see it, they want it, so I understand not being able to convince him else wise.

Good luck with the wall. Hope the town doesn't harass you. They can be a real pain sometimes.

steve

[landman]

I would ask you sales rep to take a look at the job and give his opinion. I know that if I have ?'s about a particulr install I give him a call and he comes out and looks, at no charge of course, they are willing especially if they are going to sell you the product.

[creative concepts]

PAPS

My question of are you going to charge a split pallet price for some of the blocks is that Techo block is only sold in full pallets of, I beleive for creta, is 27 sq ft. I agree with Stevair on the structural soundness of Techo block for a wall like this. Those little plastic dowels that fit in the groves just don't seem very strong and the tolerances between blocks is large. But, like you said, if the customer wants it he gets it.

I do not understand though how some can charge so cheap for this wall system since the Techo block costs about $13 per sq ft to purchase at a full pallet. If this were a regular block wall (i.e. keystone, diamond, E.P. Henry, Grinnel etc...) than I would agree with the other prices of about $30,000.00. If I figured this out correctly, that means you will only make about a 7-10% profit on this job after all is said and done. Just figured I would add my 2 cents worth.


Chris
Creative Concepts

[kutnkru]

Originally posted by creative concepts
... I do not understand though how some can charge so cheap for this wall system since the Techo block costs about $13 per sq ft to purchase at a full pallet. ...The way that I see it is that the pricing structure for materials by a company who builds hundreds of thousands of feet of wall per year is much different than someone who only builds several hundred feet.

Its virtually impossible for a smaller guy like myself to out bid an operation of Pauls magnitude successfully. what might cost you or I $13 can cost them $3-4.

[PAPS]

Like i said before... the job is really only like 900-1000 sq. ft. So at 900 sq. ft X $35.00/sq. ft = $31,500. Thats how i got my number, and everyone else besides you agreed that it was a decent number

[creative concepts]

PAPS

The price I estimated was for the original measurements you gave. Since there is only 900 sq ft with no stairs or extra drainage work needed and there is easy access to the areas, that is a reasonable price.

[kris]

Paul ... I did not know that you taught this stuff... In doing tiered walls would you say (in general) that the distance between two walls must be at least 2 x the height of the lower wall to perform independently???

Also please .... this wall is next to a cemetery(will be Allan block) ... because of this, the construction zone behind the wall IS LIMITED to 3 ft ... the wall is 8 ft high and in clean sand/gravel. I need a acceptable solution.... fellow mentioned masonry reinforcement which I have never done . I was thinking perhaps a 2 ft deep gravity wall (double wall)... any comments or suggestions ?

[paul]

Kris, Double walls are tricky without knowing how other forces are going to react to your second (highwall) I couldn't tell you right off hand. parking areas, traffic (foot, mowers, golf carts) all can affect your wall, along with water run off, ground water and soil mositure%. Other things like compactoin ratings of the subsoil and back fill also play a big part of the design.


For your other question a 8' wall could be done with 3' working room on the back side. I wonder if you could reniforce the toe of the wall with a 16" x 6" concrete curb with 2 #5 rebar and then use three foot grid sections every 18" going up. You might want to look into soil nailing also, but I don't think that they make them that short. My main concern would be if I built it would I be able to remove any water away from the top of the wall by regrading the top or redirecting water way from the wall and making sure my fill cap was impermable, not allowing any water to penatrate to the wall. Hopefully it won't have any traffic at the top other than a hand mower or weed whip, I also wouldn't use it for plantings.

[kris]

Thank-you ... I like the sounds of the curbing and will check to see if this is acceptable.

Can I please pick your brain a bit more ...... a client is asking that we put fabric behind the wall...... his thinking being that it will stop washout through any small gaps ...
My position is NO .... my reasoning is that the fabric could cause the infill area to become saturated and will increase the hydrostatic pressure ...possibly causing the wall to fail.... any wisdom on this?

thanks in advance

[paul]

Stick with your gut:)

No fabric should be used unless your dealing with heavy clay soils, but thats a whole other story!

[steveair]

Hello,

this reminds me of a few jobs where we built walls to make grade for a septic leach field.

The walls were 4 ft and the engineer had plastic behind the walls........I wonder what kind of complications that brings.

From my own experiences, a substantial amount of 3/4 clean behind the wall solves the problem of soil washing out through the wall. The only problem arise at the top. For the first year, water runoff at the top of the wall washes some surface dirt into and out of the top few layers of block down the rest of the wall. However, after about a year, this stops as the soil/stone eventually 'plugs' up those top gaps and eliminates the problems.

steve

[Stonehenge]

According to the engineers at Versa-Lok:

If you are building tiered walls, and the distance between the walls is 2X or more than the height of the LOWER wall, you can treat them as independant walls.

They also recently had a change of heart about fabric behind walls - they used to reccommend always doing it, now their thoughts are in line with yours, Kris: silt gets caught in the fabric, clogging it up, making the chance for higher hydro forces greater.

Versa-Lok Brute is one mean mutha...

But this is all according to Versa-Lok.