Pouring Concrete Slab

[MapleME]

Im about a week away from pouring a 12x20 concrete pad for the new sugarhouse/shed. The sugarhouse will be 12x16 and 4 feet of the pad will stick out to hold some wood under a shed-roof.

anyway, I am building the frame for a 6 inch pad. I have 2 questions. Can I get away with a 4" pad if I use rebar for some added support in the concrete

second question...I have built the frame on the ground. No site prep done inside the frame. There are a few stumps, and its just all dirt. I wasn't planning on putting any plastic down, sand etc etc. since Im on a pretty strict budget and I also need a new deer rifle :)

For you construction savy/folks who have done this...sound ok?

The plan is to have Dragon concrete come dump it, I will screed with a 2x4 and be done with it.

if Im about to make some fatal errors, let me know.

Thanks all

[brookledge]

I hate to spoil your day but the pad will only be as good as your prep work below grade. I would remove all stumps and get good drainage material underneath like crushed stone or gravel. It sounds like you still have loam there by your desciption. Frost will wreak havic with you and it will crack. Check with othewrs to get ther opinion but I wouldn't spend any money on concrete until I got the base prepared
Keith

[mtnmeadowmplfarm]

MapleME,

You need to use rebar even with a 6" slab. If you are not prepping the base with any good aggregate I hope you are prepared for a lot of cracking and heaving. Maybe you should eliminate concrete under the woodshed and use that extra money for some good base material. Bank run gravel would be sufficient and the most cost effective, or for a little more $ get crushed gravel, it is a little easier to work with. With a 12x16 slab, one 14yd load of gravel would be enough to prep a base appx 18" deep. I know I can get a load of bank run for around $225. I'm not sure what you have available to move dirt but you would need to remove the top 18" of soil from the site.

A little extra time and money now will save you big time in the long run.
Once you mess up a slab your only choice will be to do it over, which would be quite difficult with a sugarhouse sitting on it.

[PerryW]

Agree w/ the other responses. You gotta get the stumps and loam out of there and replace with stone or gravel.

If that is too expensive, you could also just build the sugarhouse on blocks or piers (with a wood framed floor) and just pour a small pad for the firebox of the evaporator instead.

This sugarhouse has lasted 21 years and I just plopped down some cinder blocks and built a wood floor right over the stumps.

http://i6.photobucket.com/albums/y235/perryW/SugarhouseSteam.jpg

[Haynes Forest Products]

You have to get the top layer removed for underlayment.....period As things rot and settle its all at differant rates so the cement will crack and heave. And everything that sits on it will do the same. Change your budget. Rebar doesnt keep cement from cracking it only keeps it from separating.

[KenWP]

My garage has the pad poured on sand by the idiot that built this place. I had to cut the bottom of the door to my shop off a inch so that I can open it in the winter. It's all cracked to hell and gets worse every year and I have only been here a year so if you can afford it put a good base of gravel under the pad.

[WESTVIRGINIAMAPLER]

Plastic underneath concrete is important as it keeps all the water from getting sucked out of the concrete from the bottom so it dries properly and even. With anything in construction, any shortcuts you take comes back to really bite you, especially with concrete.

[Haynes Forest Products]

Whats cheap in the beginning is the most expensive in the end. 6" is better than 4" the labor is the same and rebar is cheap. Then we have the floor drains about $50.00 and well worth it. You said your just going to level with a 2x4 and call it good:cry: You will curse the day you didnt rent a bull float and get it as smooth as possibe. When it comes to sweeping out the firewood dirt you will be fighting the rough surface everyday.

[ennismaple]

I agree with everyone about the prep work. I'll be preparing a site for one of my tank buildings this coming weekend. First, I'll level off all the topsoil, put down a 12" thick layer of 3/4" clear stone and then form it for the concrete - likely 8" thick. When you place rebar in concrete you need to ensure it is embedded at least 2". In a floor slab this mean's it's 2" clear from the bottom. Allowing about 1" for the steel (which is conservative - you're probably using 10M or 15M bars) and 4" above the steel you're at 7".

I don't mean to rain on your parade but if you do it right now you won't regret cutting corners later. You can always get that new rifle next year!

[red maples]

I am putting in a barn and having someone do the slab and he recomended using concrete with fibers said it doesn't rustaway like wire fence ane rebar. and it is just as strong!!

[MapleME]

Whats cheap in the beginning is the most expensive in the end. 6" is better than 4" the labor is the same and rebar is cheap. Then we have the floor drains about $50.00 and well worth it. You said your just goimg to level with a 2x4 and call it good:cry: You will curse the day you didnt rent a bull float and get it as smooth as possibe. When it comes to sweeping out the firewood dirt you will be fighting the rough surface everyday.

Thanks for the constructive advice Haynes. So, plastic between my crushed stone and the concrete?

[KenWP]

My other guestion was going to be what kind of deer rifle. I have to go through people that figure just because I make syrup and own land that I make a fourtune on the stuff. Ha Ha All these updates to improve production do not come cheap.

[StewieSugar]

I am putting in a barn and having someone do the slab and he recomended using concrete with fibers said it doesn't rustaway like wire fence ane rebar. and it is just as strong!!

I had two friends try the fiber-reinforced concrete, and they have mixed opinions. Neither of them put in any rebar or mesh, and both are 4" thick slabs that have not cracked at all in several years.

The three downsides of using, best I can tell, are:
* it costs a bit more than rebar
* it's a bit more work to trowel (fibers can bunch up)
* after it's cured, the fibers stick up from the surface

One of my friends uses his shed for his shop, and he lays on the concrete to get under his tractor and truck. For the first few years, he said the fibers would poke him in the back and make him itch. The other guy says the fibers break off for the first few heavy sweepings, and the fibers can get in the air.

I'm not sure how fine these fibers are or if these guys are just picky, but I recently poured 29 yards in my shed, and I avoided the fibers and went traditional.

[MapleME]

ha. Well, the rifle is a model 70 is 30-06. I cant wipe that out of the budget this year. I said that last year and tried slugs through my shotgun, what a mess that was. Like lobbing a softball.

I will spend some extra $ on some crusher run and pour on that.

[dnap63]

I would like to add a couple of things, I have been in the concrete construction business for years, like others have said take the time and prepare your site. Concrete is not cheap and it is a lot harder to fix a problem after the fact than prevent it with proper site prep. spend the money for plactic it functions as a vapor barrier and helps keep moisture out. moisture can be a problem especially in an unheated building. I would also recommend the fibermesh added to the concrete, it does a good job reinforcing the concrete often better than wire mesh. Wire mesh is designed to work if it is in the middle of the slab too often it ends up close to if not on the bottom of the the slab. lastly you indicated that you wanted to screed the concrete with a 2x4 and leave it. You really should at least go over it with a bull float and if possible hit it with a trowel to get a decent finish to your floor. Remember a bad floor is going to cost you the same as one with a nice finish. There are 3 gaurantees with concrete, 1 it will get hard, 2 it will change color, and 3 it WILL crack.

[Parker]

I worked concrete for a number of years,,,,as all the others have said proper site prep is your first important step,,,dont forget to compact the area where the slab is going!YOu dont want the fill to settel after a few freeze-thaw cycles,,,,- Then plastic,,,,then form,,dont know how much experiance you have with concrete,,,,but to form get a sight level (or laser)-shot a grade set your forms to the grade,back fill the forms with dirt to keep them from blowing out,have your 2x4 screed handy at this point,,,if the screed dosent reach from form board to form board the put a grade stake (can be a board with a nail) inbetween them (like in the middel of the slab) pour your concrete as stiff as you can (within reason) do a section at a time-level it -screed it bull float it-do the next section till its all in there- once you have the crete all floated go around the edges with a magnesium trowell- this will knock the rocks down and bring the "cream" to the surface,,,once the slab sets up a littel (if you step on it you dont sink in more than 1/4") take 2 peices of 1" blue (insulation) board cut about 2'x2' put them on the slab-get on the on your knees and work your way across the whole slab maging the surface,staying on top of the boards,make it as smooth as you can,,,if you dont mag (at least) the slab the pours of the crete wont seal and every time you sweep it it will be dusty-water can get in the surface, freeze and pop up the surface,,,,,,,,,,,,,if your really into it once you done maging you can go over the surface with a steel trowell,,,,,someting your size wont take too long to finish,,,,,if your ever in NH you can stop and grab my bullfloat-mag and steel trowels-kneeboards,,make sure you have some water hany when your done to clean everything,I do like fibermesh as its 3 dementional reinforcement-rebar if done corectly, is also a big help (not the right way to do it but as you are pouring after you screed-befor you bullfloat drop the rebar in and push it into the crete with your lute-rake,you want it in the middel of the slab,,,,,,,,,,,-wire (imho) just holds the crete together when your jackhammering it out,,,,,,6" thick is alot stronger than 4",,,,GOOD LUCK

[MapleME]

this is all really helpful since its probably obvious I have never worked with concrete or built anything for that matter. I just ask a lot of questions, read and try to surround myself with people who dont mistake inexperience with ignorance. Bull Float rental is 15 bucks, obviously worth the time/energy to get it right. Oh, and I will stick with 6".

[red maples]

What I am doing in the barn Which will be 24x30 is putting in a 10 x16 walkin freezer so that part of the slab will be insulated with 6 mil plastic 4 inches of foam board 6mil plastic then 6 inches of concrete outlined by Pressure treated 2x and 12 inches thick and around the outside border of the entire barn (don't remember what that type of slab is called) and 6" thick on the rest and fibers in the concrete got a quote of $2700 that includes digging too. does that sould like a good deal or no?? still have to get estimates from 2 other guys but for those in the business what do you think??

[Haynes Forest Products]

24x30 all materials and labor go for the best price after calling a few refrences Ask them to put in writing 1/2 paid when all backfill and forming is done and all trash is removed . After you decide on the contractor you want to do the work explain that he gets the job if he does floor DRAINSSSS (2) sit back and have a cold one as the work is done

[red maples]

yes, he is putting in the floor drains and anchor bolts as well. I am building the barn myself it will be finished and insulated on the inside too. bottom for me top for my wife's art studio.

[3rdgen.maple]

HMMMMMMM how is she gonna paint in all the steam..........:D I think you are tricking her into the barn and when she can't see anything up there you plan on taking over the "ART STUDIO";)

[Gary R]

Red Maples,

I believe your talking about a monolithic pour. I'm not in the business. Your floor is going to take about 15 yards of concrete. Around here it goes for about $100/yard without fiber mesh. If their doing the entire slab, it's sounds like a decent deal. Good luck.

[red maples]

OH yeah thats the name...thanks

no the barn is for an ice carving business no steam in There just electric tool noises that she will have to deal with, electric chainsaw, die grinders, and angle grinder. she'll just have to turn her I-pod up a little louder to drown me out even though I will be in the walk-in. :D the walk in freezer will be used to store my syrup in too.;) and if I have enough space after I get my ice block maker then I will put in a lttle syrup finishing kitchen for candy and botttling and stuff like that.

making a sheep barn style. the main gable will be 15x24 with a 6 foot knee wall upstairs and then short roof will come off the knee wall to the other side. Putting in a green Metal Roof. Pellet stove for heat, the bottom will be sheet rock but the top (art studio) will be tounge and grove pine hung at 45 degrees...(I will do the top first then if I feel Like I have enough energy maybe I will do th epine down stairs too...anyway should be really sexy when I am done!!! its a ton of work when your doing it yourself though. hopefully I will be done by suagring time. Btu it won't interupt sugaring believe me!!!!

[maple maniac65]

I spent this morning lugging 4000# concrete to the sugarhouse in 5 gallon buckets with the 4 wheeler and trailer. It took 6 trips for 3 1/2 yards. This was done in less than two hours. I had a pad there that lasted 10 years but it was mixed by hand and poured on a dirt floor with no prep work. It cracked and heaved in time.

I hope to never have to do this again. The next sugar house will be built where a cement truck can get to it.

[Fred Henderson]

You want that SH close to where you live to help in preventing theft. Sort of being able to keep an eye on things.

[WESTVIRGINIAMAPLER]

A tractor with a good size loader bucket on the front works good for hauling concrete to remote locations. Quick load and unload.

[GeneralStark]

Reviving this thread instead of starting a new one. I will be putting up a new sugarhouse this fall. Timber Frame 14x18 on an on grade slab. The soils we are building on are excessively drained sand and gravel, so I am planning to have our excavator scrape off the topsoil and get down to the subsoil and then bring in some gravel (12-16"), though me may be able to use some material from the site, and pour the slab on that. My questions are:

Is it worth doing a footing or frost wall or should I just do a monolithic slab? I am planning 6" with rebar.

I am planning on two floor drains, one in the evap. room and one in the eventual ro room. We are on top of a plateau with a good slope below the building site. Should I just daylight the floor drains or use a french drain under or next to the slab? I could theoretically connect them to our septic tank as well as the sink in the SH will be connected to that anyway.

What are folks doing for RO drains? Perforated pipes in gravel trenches?

I planning to have the water supply line come into the heated RO and pump room (6x6), and have the sink in the unheated portion. When it gets below freezing I will drain the water line back to the heated room. The sink will drain to the septic tank. Is there any need to have the sink drain in the heated room?

Is it worth insulating the portion of the slab under the RO room?

Any thoughts are appreciated.

[ennismaple]

A monlithic (floating) slab should suffice. It sounds like your soils are free draining so putting a foot of stone beneath the 6" reinforced slab is about right.

The more floor drains you have the better! One is absolutely necessary in the RO room to dump the excess permeate and for cleanup. The best sugar camp setups I've seen have a trench drain along the sides of the evaporator. It makes cleanup so much easier!

For our RO drain we put a rigid pipe beneath the concrete slab with a buried perforated pipe going down the hill 150ft or so away from the camp.

[OldManMaple]

Don't connect your floor drains to your septic unless you have no other options. And if you do be sure to have a wet trap to avoid sewer gas. Also if your sink drain has a trap put a drain in the trap. Yes insulate your ro room floor.

[PerryFamily]

I say do it right the first time. I am in the excavation business and have done a lot of work for people with drainage issues, prep for concrete and asphalt.....

But when it came to my own sugar house......well I did what irritates me the most with customers.....I went cheap and regret it!!!

My 4" slab with fibers now has a crack right down the middle which sucks. Although it has not effected the level of the evaporator....yet

As stated above, 12" of good well compacted crushed gravel is perfect. I have done a lot of " alaskan" or "floating" slabs with good results.

6" floor, with a 12" x 12" honch, or thickened edge around the perimeter. Fibers are OK but are hard to finish. The slab always looks hairy and rough.
rebar or mesh is better.

As far as the drains, I wouldn't put anything into your septic system except for a toilet and maybe sink. Everything else I would just daylight. But if your soil drains good, perforated pipe and stone might work good too but I would day light it as well.

[Flat Lander Sugaring]

one drain each side of arch unless you do all draws from one side. Build a canner room also, you will want hot and cold water in there also. Make sure all areas will meet what could be the new sugar house codes coming soon to your area wash down, sanitation etc.. I used fiber crete with 1/2 or 3/4 rebar every 12" and my floor still cracked. I want to expoxy it this summer with a non slip finish.

[Moser's Maple]

General I'd go with the monolithic slab, and as stated before, do a 12x12 honch around the outside. I would probably go a step further since we are talking ro and heated area. 12-16in of compacted gravel is great. I would then lay down 6mil poly to keep the concrete from wanting to sweat. I would also lay down ridged Styrofoam under you slab honch and outside the slab. (so if you have a 12in honch I would cut a 4x8 sheet in half so you have half in and half out) then depending on if you are doing a roll or 2 of blocks I would rip a piece of insulation to go from your honch insulation to you blocks. you are trying to create a thermal barrier for your concrete slab. I would also floor cut the concrete slab. it's a fact all concrete cracks, just different degrees of cracking occurs. if you cut your floor you give the floor a controlled relief for the crack to occur. you can fill the floor cut with either NP1 caulking or SL1 caulking. just ask your local hardware store for other brands that would work. Lastly I would purpose a quality concrete sealer such as "Kure n Seal" unless you plan on epoxying or painting the concrete. Kure n seal can be applied the same day after the floor has set up and helps with the curing process. The floor cut should be made the following day. for a 14x18 slab I would make a cut at 7 foot and 9 foot turning the slab into fourths

[TheMapleMoose]

Just a few opinions from my own experience here but if it was mine, I wouldn't bother with the thickened edge. It makes a place that is more prone to break. 50 guys might tell you how much better it is but we have built hundreds of buildings on a uniform thickness slab, usually 6", and we make out great doing them that way. Most slabs will crack regardless, even with the best prep but its the rebar that keeps it from opening and moving. Wire mesh will be rusted and gone in 5 years. Don't waste your money, spend it on rebar, put it in 2' o.c both directions.
Absolutely put poly under, 6mil preferably. If you are going to heat it I would put 2" foam under. It will "help" with frost and sweating and you'd be amazed how much easier it is on your legs and feet working on a slab with foam beneath. For 6 sheets of foam it's worth it.
We almost always install pex for the option of radiant heat, but that's up to you.
The other guys have pretty much covered the ground work. I would add some perforated sch20 in the stone or gravel base then change to solid and run to daylight. If you can run to daylight that is always the best option for a drain. We run our RO drain to daylight as well.

[Michael Greer]

Concrete lasts forever, and bad concrete work will be there to annoy you forever too. Take out the topsoil...it won't cost anything but labor time. Put in sand or gravel...it's cheaper than anything else you can buy, including concrete. Put 6 inch mesh in it and re-bar around the edges. Get some friend who'll work for beer to help put a finish on it. The sugar house generates plenty of dirt, and you'll have to sweep up every day, so why not make your life easier. There's too much half-a**ed concrete in the world already, and it's a curse to whoever comes after you.

[Maplehobbyist]

My current shack is on piers and has a dirt floor. My dry block and brick evaporator sank under the firebox a little this past season, I think because it melted the frozen ground, and I would like to put in a slab, preferably for the whole floor, but possibly only under the evaporator if doing the whole thing is unfeasible. The interior space is 7'6" x 8'3". All the work will have to be done by hand as it's not possible to get a machine in there. I'm most concerned with preventing it from becoming uneven, either from frost heave or cracking. It would be possible to get 6" of gravel and a 6" slab if I only did under the evaporator, but it will be difficult to impossible to dig down deep enough to get that for the entire floor. For an area that small (less than 62 sqft) would I need a 6" slab? Would I only be asking for problems if I went thinner on either the gravel bed or the slab? I don't want to do it if it's going to be crappy in a couple of years. Are there any other possibilities for a level floor that I'm not considering?

[Moser's Maple]

being that small I think you could get away with a uninsulated floating slab, as long as you do the following to ensure it won't crack. If you go with 5 inches of concrete that will on be 1 cubic yard worth of concrete. I'm not sure how many bags that would be, but if you ask somebody will be able to help you. You could also make your own with bag Portland, sand, and stone. Once again ask at your local lumber yard and they should be able to help you. If this was my place this is what I would do.... as long as the dirt isn't pure topsoil just remove enough to get your 5 inches of concrete. rent a plate compactor and wet your area to be pour and compact it till it moves no more. put down some plastic, then lay out rebar grid work 1 foot by 1 foot squares. 1/2 in bar should be more than good enough for this. if you can get 20 foot bar then your only talking like 9 pieces to do this. buy a roll of foundation sill sealer, and some contact spray. this is to put around your pillars to make sure your slab is going to free float from the rest of the building. purchase concrete chairs to go under each grid pattern to suspend your grid work 2 inches of the dirt and in your concrete. then go ahead and pour your floor.

[TheMapleMoose]

It takes 54 bags of premix to make a cubic yard. There is only 1/2 cu ft per bag.

[unc23win]

This is mine I poured on Tuesday. [ATTACH=CONFIG]
By the way there are quite a few apps for calculating concrete, gravel, morter and such that are free and there are also web sites that do it as well. I use one on my iphone that calculates all of the above and more.

As they say there are two kinds of concrete that which is cracked and that will crack. You never know for sure.

[GeneralStark]

Just finished the prep. for the new sugarhouse slab.

7950

[unc23win]

looks good How big is your General?

[GeneralStark]

14'x24' with 14'x14' sheds on each end. There's room to add on down the road of necessary.

[unc23win]

Cool I am doing 30x36 for now maybe some sheds later on.

[GeneralStark]

Ready for the cement truck.

8005

[PerryFamily]

Looks Awesome General!!

[unc23win]

Looks good nice job!

[GeneralStark]

Thanks guys! All your advice has been very helpful. I'll keep posting pics as things progress.

[PerryFamily]

General- My slab for my RO room addition is ready to go as well. Just waiting on concrete. Putting $700 in the wife's car set me back a few days.

I ended up going with 1 floor drain and radiant in the concrete. Should get it poured on Tuesday. Gotta hurry up, winter will be here soon!!

[GeneralStark]

I am pouring two slabs this week (hopefully) as long as my hired help can fit it in. One for the sugar house and one for the slab. I wasn't planning on putting pex in the sugarhouse, but now I think I will in the heated room area. Too easy and cheap not too. What is the cheapest, easiest method to connect one loop to a heating source? Manifold?

Not sugarhouse releated but here is the slab for the home.

80068007

[maple flats]

At least you won't get cornered in that home. (I'll bet you never heard that before!) What diameter is it?

[PerryFamily]

General- I leave the plumbing to my plumber buddy but i know it is just another zone so there will be a thermostat and circulator pump for the floor. Then there is a a plate heat exchanger for hot water so the two dont mix. A 300a foot roll of heat pex at webb is like $260 and you can rent the tool to staple the tubing to the styrofoam from webb too for $35.
Super simple.

[BreezyHill]

Check out farm tek for pex products....I got all my products there due to quality products. I had a friend braze a manifold for me out of copper 2" to 3/4 for sweat valves. I know several places use an electric hot water heater at the lowest setting for a heat source. They claim it is supper cost affective. I use a outside wood boiler. I have an 1843 built brick farm house. The kitchen has a crawl space under and was always a cold floor. Pexed and bubble rap from FT made a nice 75 degree floor. Now in the winter the floor is never wet very long after snowmobiling. It took my son and I about 2 hours to do two loops and insulate. Becareful with the slab when pouring, the pipe can float. Really ugly when it gets onto the power trowel. Saw that one time. Not pretty.

[GeneralStark]

At least you won't get cornered in that home. (I'll bet you never heard that before!) What diameter is it?

We hear that often. 24'

[GeneralStark]

I'm being really careful with the pex as I zip tie it to the rerod so it won't be able to rise to the surface. I will also be pressure testing the tubing as we pour the cement just in case.

In our home I am thinking of using an electric water heater for our domestic hot water and for the hot water for the radiant. This is a pretty common practice, and because space is limited killing two birds with one stone is ideal. For the sugarhouse heated room I am also thinking about a small hot water heater as I will be wanting hot water for the sink there as well. I got a pretty simple and well built 2-loop manifold for the home system with a "kit" including 2-300' rolls of pex. I think I can build something pretty simple for the sugarhouse room.

[GeneralStark]

Poured the slabs on thursday, and despite some issues with the concrete (too much bleed water), they turned out great. Our concrete guy was there til 8 despite starting to pour at 8:30.

So, considering all the advice from you guys this is how it ended up.

- 18-24" of gravel for bedding.
- 6 mil plastic.
- 1" foam board
- 1/2" rebar, doubled and 6" apart around edge on rebar chairs (these work slick)
- 2 floor drains (one in evap. room under draw off area and one in heated room) to day light.
- Wastewater line, water line and conduit for 200 Amp service (all to heated room except wastewater)
- 1/2" pex in slab under heated room
- 6" final thickness with no thickened edge. Several recommended against it due to size and " light" nature of building.
- Two coats of clear sealer. I definitely recommend this as it really makes the floor easy to clean.

Now it is time to start cutting the frame and putting it up. Should be up by early November.

80218022