Concrete help ?

[R Socey]

My brother is going to let me put my boat at his house, but we need to pour two slabs 50'x20' - 16'x25' 4" deep. I just got an estimate for $9,000.00 - seems high to me; I don't know? We are in one the highest cost of living locals - Mongomery county MD just outside of Wash DC - are nations crapital. I plan to get a couple more quotes, but if they are going to be in that proximity It would be feasible to do the brunt of the work myself.
I have never used a bobcat but there is a place just up the street that will drop off, and pickup. I can just leave the dirt onsight. Any advise would be greatly appreciated. My boat is an hour away from me which makes it hard to work on. My brother's place is 15 minutes with perks!

 

[minuteman62-64]

Re: Concrete help ?

OK, so you've got 1400 square feet of surface and will need close to 20 cubic yards to pour. I looked for my old paperwork but couldn't find it - but, as best I can recall the last concrete I had poured ran about $360/cubic yard and about $1/square foot for finishing (in San Diego - pretty high cost also).

Sooo, that would work out to be about $7200 for concrete (figure 20 cubic yards) and $1400 to pour and finish = $8600. If your prices are comparable (easy to check with a couple of phone calls) you're getting the excavation and form setting for $400 - doesn't seem a bad price.

What I'd do is enlist my brothers assistance, rent the Bobcat (easy to learn and fun to use on level ground) and do the leveling and form setting. Then call on a pro to do the finishing. Finishing 1400 square feet of slab is, IMHO, a nasty job.

Make sure you are clear with the finishing guy on who is purchasing the concrete or you'll get a big surprise when the concrete trucks arrive

 

[jigngrub]

Re: Concrete help ?

Make videos of you operating that Bobcat, they'll be fun to watch later. Saw an inexperienced operator climb a chain link fence with one once

Get more estimates and go with the middle one, not the cheapest.

 

[sam60]

Re: Concrete help ?

When you excavate and tell the contractor to prep and pour on your dig, you risk the exposure of losing your claim if you experience cracking, heaving, etc. You need a qualified contractor to perform all of the tasks IMHO. Have all of the bidders include the proposed concrete psi, reinforcement data and square footage of control joints. Are permits included in the quote? This will give you a little better idea of a comparison than the middle price.

The real purpose of the post was to poke the ribs of jigngrub as he practices it on a regular basis and was due.

 

[Bob_VT]

Re: Concrete help ?

Do you think 4" is good enough for the frost? It will require allot of wire mesh too.

Why not just make a nice compacted gravel surface?

 

[hungupthespikes]

Re: Concrete help ?

Around here, if it's concrete it's permanent and taxed. If gravel, limestone, blacktop?, etc. then it's not permanent and not taxed.
Your pouring a lot of sq ft of pad, so looking at the tax laws and building restrictions in your area first, might change you plans.

 

[R Socey]

Re: Concrete help ?

OK, so you've got 1400 square feet of surface and will need close to 20 cubic yards to pour. I looked for my old paperwork but couldn't find it - but, as best I can recall the last concrete I had poured ran about $360/cubic yard and about $1/square foot for finishing (in San Diego - pretty high cost also).

Sooo, that would work out to be about $7200 for concrete (figure 20 cubic yards) and $1400 to pour and finish = $8600. If your prices are comparable (easy to check with a couple of phone calls) you're getting the excavation and form setting for $400 - doesn't seem a bad price.

What I'd do is enlist my brothers assistance, rent the Bobcat (easy to learn and fun to use on level ground) and do the leveling and form setting. Then call on a pro to do the finishing. Finishing 1400 square feet of slab is, IMHO, a nasty job.

Make sure you are clear with the finishing guy on who is purchasing the concrete or you'll get a big surprise when the concrete trucks arrive

After pondering, I am in agreement with you. Iv'e watched some vidios, and I have no trepidation at all about operating equiipment.

Make videos of you operating that Bobcat, they'll be fun to watch later. Saw an inexperienced operator climb a chain link fence with one once

Get more estimates and go with the middle one, not the cheapest.

Thanks for the vote of confidence. How do you think you get experience? Most operators I see don't look like Einsteins or superlatively adroit. Come on man tell the truth - it was you that climed the fence

Do you think 4" is good enough for the frost? It will require allot of wire mesh too. 4" is the norm around here - they also incorperate fiberglass in there mix.

Why not just make a nice compacted gravel surface?

It isn't my house - my brother wants concrete; he wants a nice hard flat surface to work on his vehicles.

 

[R Socey]

Re: Concrete help ?

When you excavate and tell the contractor to prep and pour on your dig, you risk the exposure of losing your claim if you experience cracking, heaving, etc. You need a qualified contractor to perform all of the tasks IMHO. Have all of the bidders include the proposed concrete psi, reinforcement data and square footage of control joints. Are permits included in the quote? This will give you a little better idea of a comparison than the middle price.

The real purpose of the post was to poke the ribs of jigngrub as he practices it on a regular basis and was due.

Thanks for those considerations - whats wrong with that guy

Around here, if it's concrete it's permanent and taxed. If gravel, limestone, blacktop?, etc. then it's not permanent and not taxed.
Your pouring a lot of sq ft of pad, so looking at the tax laws and building restrictions in your area first, might change you plans.

It's ok to pour - paying taxes is nothing new.

 

[dingbat]

Re: Concrete help ?

Around here, if it's concrete it's permanent and taxed. If gravel, limestone, blacktop?, etc. then it's not permanent and not taxed.

Maryland could care less what your drive is made out of. You’re assessed on the value of the properly based upon its location and it's current market value. The way property values rise around here, you can count on a 10% annual increase in your property tax no matter what you do.

 

[minuteman62-64]

Re: Concrete help ?

Need to keep it real on this. As I understand, you want a concrete pad for parking a boat and working on cars, not landing B-52's. Comments about compaction, slab thickness, reinforcement, etc. are all valid. But, you don't need much more than would be involved with the typical concrete driveway in your area. Here, in So. Cal., (where we do not have a frost issue) that means reasonably compacted native subgrade, a slab w/thickness ranging between 3" and 4" (depending on how carefully the grading and formwork is done), 1750 psi concrete and no reinforcement.

I suggest taking a look at how concrete driveways are constructed in your area and using that as the target. Regardless of the practice in your area, I would use steel (for me #3 bars in a 16" or 18" grid, since I don't like working with rolls of mesh). For a job of your size it won't cost much and it's an easy do-it-yourself job to lay it out and tie it.

 

[Bob_VT]

Re: Concrete help ?

It's ok to pour - paying taxes is nothing new.

You pour tea and PLACE concrete!!

20 years in The US Army as a Construction Engineer and that was pounded into us all the time at every concrete job!

 

[R Socey]

Re: Concrete help ?

Need to keep it real on this. As I understand, you want a concrete pad for parking a boat and working on cars, not landing B-52's. Comments about compaction, slab thickness, reinforcement, etc. are all valid. But, you don't need much more than would be involved with the typical concrete driveway in your area. Here, in So. Cal., (where we do not have a frost issue) that means reasonably compacted native subgrade, a slab w/thickness ranging between 3" and 4" (depending on how carefully the grading and formwork is done), 1750 psi concrete and no reinforcement.

I suggest taking a look at how concrete driveways are constructed in your area and using that as the target. Regardless of the practice in your area, I would use steel (for me #3 bars in a 16" or 18" grid, since I don't like working with rolls of mesh). For a job of your size it won't cost much and it's an easy do-it-yourself job to lay it out and tie it.

The 20'x50' can be done first just so the trailer/boat don't sit in the mud - it's going to sit for 2, years. I've watched a bunch on you tube, and I'm use to hard work! Thanks for the encouragement, and advise.

You pour tea and PLACE concrete!!

20 years in The US Army as a Construction Engineer and that was pounded into us all the time at every concrete job!

I was a Marine 0341 - I have no idea what that means?

 

[minuteman62-64]

Re: Concrete help ?

: You pour tea and PLACE concrete!!

20 years in The US Army as a Construction Engineer and that was pounded into us all the time at every concrete job!

Uh oh. I guess you'd be all over me when I call concrete blocks "masonary" materials .

 

[Bob_VT]

Re: Concrete help ?

I was a Marine 0341 - I have no idea what that means?

Thanks for your service brother!!

LOL I built allot with PSP steel too

 

[Tyrannosaurus]

Re: Concrete help ?

Lots of good advice from others regarding placing concrete slabs; some not exactly correct or a little incomplete, though. If you?re going to try to do most yourself, some additional thoughts from another engineer:
-- Have EVERYTHING planned out in detail and prepared in advance of concrete delivery, because once concrete starts flowing, it must continue to completion.
-- Not less than 4? thickness. 3000 psi is common.
-- Make sure you and the finisher are also clear on exactly where the division of labor is ? will he/she be screeding, as well as floating, troweling, brooming??
-- Include at least one expansion joint across the middle of each, with contraction joints (tooled or post-cut) further breaking up the large panels. Contraction joints should penetrate at least 1/4 thickness of the slab; half of reinforcement should be cut at those lines (i.e. plan exactly where they will be). Google spacing recommendations.
-- Reinforce with welded wire fabric. I understand the comment about #3 bars, but 16?+ spacing is far too wide for thin slabs and the bars should be tied together, which is a pain. WWF is relatively inexpensive and well-suited to slab construction. Straighten it ahead of time and set it up on concrete blocks so it?s right in the middle of the slab ? the WWF supplier will have them.
-- Get your expansion joint materials, WWF, sealer from a contractors? supplier and pick his brain, too.
-- Subgrade prep is as important for a driveway as it is for a highway.
-- Slope for drainage ? 1/4 inch per foot is good; never less than 1/8 in/ft. Prepare the foundation accordingly so the slab can be of uniform thickness.
-- Have the surface broomed (or apply other non-slip finish) for safety.
-- DC is still in what is considered a severe weathering region, so air entrainment is desirable for long-term durability.
-- Maximum coarse aggregate size should not exceed 1/3 the slab thickness.
-- PROPERLY CURE THE CONCRETE for at least 7 days ? extremely important for durability. Moist cure is best using burlap or non-staining sand and soaker hoses or light sprinklers, but don?t send a stream of water across the slab. Curing/sealing compounds are second-best. Moist curing also mitigates slab curling from surface drying.
-- Seal the concrete before winter.
-- If you can, wait until fall when the weather is cooler and damper.

Didn?t mean to be so long-winded. Have fun?

 

[rbh]

Re: Concrete help ?

this is my second attempt, first time it kicked me out for being to slow, stupid PUTERS!!!

I wil make my .02C fast this time.
excavate about 8 inches depth from grade (if it is totaly flat)
4 inches in depth of 3/4 minus gravel, COMPACT!!
lay out concrete mesh "REMEMBER, stake the corners down before you role it out so it doesn't take your eye out!!
now that you have it rolled out, stake down the other side loosely it is nice to have the wire up about an inch to get into the concrete.
Pour slab, float the water to surface and get it power trawled for a nice finish.
If it is to hot you may want to slow down the cure time by turning the sprinkler on it (just misting it) if it cures to fast it may crack

 

[Fishing Dude too]

Re: Concrete help ?

You may want to go 6" of crete, wire, and then just screte off with 1/4 slope for drainage per3 ft. Don't forget to cone your crete.

 

[R Socey]

Re: Concrete help ?

Lots of good advice from others regarding placing concrete slabs; some not exactly correct or a little incomplete, though. If you?re going to try to do most yourself, some additional thoughts from another engineer:
-- Have EVERYTHING planned out in detail and prepared in advance of concrete delivery, because once concrete starts flowing, it must continue to completion.
-- Not less than 4? thickness. 3000 psi is common.
-- Make sure you and the finisher are also clear on exactly where the division of labor is ? will he/she be screeding, as well as floating, troweling, brooming??
-- Include at least one expansion joint across the middle of each, with contraction joints (tooled or post-cut) further breaking up the large panels. Contraction joints should penetrate at least 1/4 thickness of the slab; half of reinforcement should be cut at those lines (i.e. plan exactly where they will be). Google spacing recommendations.
-- Reinforce with welded wire fabric. I understand the comment about #3 bars, but 16?+ spacing is far too wide for thin slabs and the bars should be tied together, which is a pain. WWF is relatively inexpensive and well-suited to slab construction. Straighten it ahead of time and set it up on concrete blocks so it?s right in the middle of the slab ? the WWF supplier will have them.
-- Get your expansion joint materials, WWF, sealer from a contractors? supplier and pick his brain, too.
-- Subgrade prep is as important for a driveway as it is for a highway.
-- Slope for drainage ? 1/4 inch per foot is good; never less than 1/8 in/ft. Prepare the foundation accordingly so the slab can be of uniform thickness.
-- Have the surface broomed (or apply other non-slip finish) for safety.
-- DC is still in what is considered a severe weathering region, so air entrainment is desirable for long-term durability.
-- Maximum coarse aggregate size should not exceed 1/3 the slab thickness.
-- PROPERLY CURE THE CONCRETE for at least 7 days ? extremely important for durability. Moist cure is best using burlap or non-staining sand and soaker hoses or light sprinklers, but don?t send a stream of water across the slab. Curing/sealing compounds are second-best. Moist curing also mitigates slab curling from surface drying.
-- Seal the concrete before winter.
-- If you can, wait until fall when the weather is cooler and damper.

Didn?t mean to be so long-winded. Have fun?

I appreciate your help: I feel this is a great responsibility as my brother is writing the checks - I want to do this right! I find the hardest part with stuff like this is the sheduling. I will study the particulars all of you have given, but it's the help I am going to enlist that gives me pause. I have a friend that ownes a dump truck buiness - so that should help!
I wonder if I should segment the work - would seperate small slabs be advantages instead of 2" expansion joints? I have the rest of this year to accomplish this! To tell you the truth, I would dig it all out by hand, and mix the concrete myself if need be -this is really a big deal; not just the monetary aspect - getting the boat done!!!

 

[rbh]

Re: Concrete help ?

OH, forgot, use 2x6s as your forms.
Screw the corners together and stakes on the outside every 2 foot going a foot into the ground a minimum 1 foot.
Rent a transit to set the height and ensure a square form.

 

[jigngrub]

Re: Concrete help ?

Thanks for the vote of confidence. How do you think you get experience? Most operators I see don't look like Einsteins or superlatively adroit. Come on man tell the truth - it was you that climed the fence.

No, actually it was my foreman at the time which gave me an even bigger kick!

I can honestly say I've done my share of the "bucking bronco" (you'll see what I mean) though. It's not as easy as it looks.

Equipment operators may not look or be very smart, but good ones are hard to come by and worth their weight in gold.

You pour tea and PLACE concrete!!

20 years in The US Army as a Construction Engineer and that was pounded into us all the time at every concrete job!

... but what about ceement? You know, ceement floors and ceement walls! I like to tell the people that use that term that it's concrete and cement is just one ingredient of concrete.

Here's a tip for Socey:

Over excavate and back fill with granular fill, most use 57 stone but I prefer 89-10. Grade you fill flat and uniform, thick and thin spots in your slab will cause undesirable cracking outside of control joints.

Ask your contractor about cut control joints instead of tooled, cut joints are deeper, usually straighter, and narrower.

4000 psi concrete withstands the elements much better than 3000, especially in a freeze thaw zone.

Rebar on chairs is much better than WWF. After the wire is tromped on by the finishers it's always at the very bottom of the slab and will rust to nothing in time.

Don't let your contractor add too much water to the concrete before placing, one of the biggest and most common mistakes made when placing concrete. If the mix "breaks" over the blades in the concrete drum on the truck, it's too dry. If the mix looks like split pea soup and comes flying down the chute it's too wet. The mix should flow over the drum blades without breaking, but be thick and come out of the end of the chute like tapioca pudding.

Ask your contractor to use a vibra strike of similar method of consolidation when placing the concrete.