How can I pour a concrete floor/slab with two levels?

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I found this thread because I wanted to pour the middle of a walkway 1/2" lower than the outside boarder of the walkway. Like the OP I wanted to tile the low portion of the concrete -- in my case the low portion is the middle strip of a walkway. I came away from this thread thinking that I would have to pay for two concrete pours on two separate days but the guys I hired did it in one pour. Here is how they did it.

The forms for the outside edges of the high areas are as you would expect -- the top edge of the forms defines the top edge of the high area of concrete. But the forms for the small step into the low areas of concrete are built so that the BOTTOM EDGE of the form defines the TOP FACE of the low areas. Also, any stakes that brace the forms for this step-down are placed INSIDE the low area and remain there during the first half of the pour.

A first screed is cut with a notch on one end that matches the height of the forms minus the step depth (e.g. 3-1/2"...

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I am pouring a slab for a concrete floor for an 1800 sq foot house and would like the bathroom area to be about 3/8" lower than the rest so I can tile it and wind up with the floor and seams that are level throughout once the tile is laid in the depressed area. How can I do this?

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Pour it first, after you've checked all of your height, length & width (including stud & drywall depth or minus those depending on your plans) measurements a googol times. If it isn't a full truck then have that truck empty 6' or more away, due to slump run.

You'll really want to let that setup completely before pouring anywhere near it. Cover it completely with 3/8's plywood & stake or screw any exterior wall edge.

You'll not only be able to walk on it, but the float work shouldn't be able to move anything...you can insure that with battens screwed over the seams. Still be careful not to knock or shift it while pouring around the room. But, that should work out...

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Pouring a concrete slab is easy if you've done it hundreds of times like we have. But if you've never done it before, pouring a slab can be a little intimidating.

Pouring concrete slabs isn't something most people do everyday. If you've ever watched someone who pours slabs for a living, they can make it look really easy. That's because they pour the slab in steps.

I'll show you how to pour a concrete slab like we do so you can have the confidence to do it yourself.

If you need to know how to prepare a concrete slab to pour, click on FORMING A CONCRETE SLAB to learn how to set up the forms and get it ready for the pour.

The tools you'll need for pouring a concrete slab are: rubber boots, gloves, magnesium screed, bullfloat, metal rakes, mag float, shovel, and maybe an extra concrete chute.

HOW TO POUR A CONCRETE SLAB:

STEP 1. After you've formed up the slab and you're all ready to go, you have to figure how much concrete you'll...

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A Guide to Concrete Construction

By Monte Burch

Concrete floors are a major component of many buildings, from homes and garages to shops and sheds. Pouring a concrete floor is hard work, and it takes skill, strength and tools. You may wish to have this job done by a pro, but you can do it yourself. The tools can be rented at many rental places, and the skills are not very difficult to learn. If you’re undecided as to whether to do it yourself or have the job done by a professional, the following steps on pouring both a slab or in-foundation floor illustrate the basics and may help you decide.

A concrete slab on which a building is erected is a fairly simple concrete pour, but it takes more work in creating the forms needed to hold the concrete. A pour within a foundation requires little in the way of forming, but in some cases can be a bit more difficult to pour, especially on larger projects. Regardless of the type of pour, or whether you do...

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Slabs made of concrete can be large or small, and have a variety of uses around the home. Unfortunately, if you have clay-heavy soil, then you may run into difficulty when pouring a slab. The clay can compress under the weight of the concrete, causing the slab to shift or sink over time. It also can leach moisture from the concrete itself, resulting in uneven curing and a brittle base. With proper preparation, however, it's possible to pour a slab on clay soil without encountering these problems.

Clear and level the area where you plan to pour the concrete slab. If the clay soil is very soft, excavate the soil to a depth of several inches and mix in gravel to create a firmer base for your slab.

Compress the clay-heavy soil in the area where you plan on building the slab using a soil tamper or yard roller. The more compressed your soil is, the less likely it is to cause significant damage to your concrete slab as a result of continued compression, and the more overall...

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Since you are pouring 4 inches there really is no need to worry about connecting to the old slab. The new slab will form perfectly to the texture of the old slab. Spraying down the old slab with bonding agent is worth your time, drilling in new bolts isn't.

This really only becomes an issue if you are only pouring 1 to 3 inches of concrete. Then there is a risk of plain concrete mixes might break apart while curing. Adding bonding agent eliminates that issue.

If the old cement is in good shape, flat and no major cracks or bulges, then there is no need to add reinforcements to the new layer on top of the old cement. However you still want to bridge the 4 inch pour to the new slab areas with a lot of rebar, or you will have significant cracking when your extended slab settles.

Also since you are pouring on plain dirt, be aware of frost bulge issues. In my area we would dig down 4 feet along all edges and fill the trench with gravel. On a hill we would just build a way...

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Can I lay ceramic tile directly on a concrete floor? -Michelle

Hi Michelle,

As long as the concrete slab is clean, flat, and free of active cracks, you can lay title directly on the concrete floor using thin-set adhesive.

Small cracks caused by shrinkage usually do not present a problem; but larger cracks, especially those that are higher on one side than the other, may telegraph through the tile and cause it to crack.

To find out if a concrete slab is clean, pour a little water on it in spots. If the water soaks in, you’re good to go. If the water beads up, it may indicate the presence of oil or wax which may cause adhesion problems with the thin-set.

To remove the oil or wax, clean the floor with a solution of TSP (trisodium phosphate) and water using a scrub brush or stiff broom. Rinse the floor with clean water to remove any residue, allow it to dry, then test it with water again.

Fill in any low spots on the slab with a...

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Is your basement or garage exceptionally chilly? An uninsulated concrete floor may be a large part of the problem. Insulating a concrete floor can save you money on your heating bill, making an attached garage or basement warmer and, by extension, the rest of your house.

In addition to offering insulation and energy savings, the plywood subfloor described here can provide the perfect foundation for finish flooring such as carpeting, adding warmth in look as well as in feel.

1To prepare for insulating the floor,

first evaluate the condition of the concrete. If you know you have issues with moisture, tend to those problems before installing the insulation. Also, check the floor for smoothness and level; you may need to grind down significantly high spots to ensure an even surface.

2Measure the distance between the slab and the ceiling; you must leave approximately 7 feet, 6 inches of clearance between the ceiling and the surface of the finished floor to comply...

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Do you have uneven floors? Don’t worry many concrete floors and floor screeds are not 100% level, and there is a solution.

Laying a concrete floor slab or floor screed over a fairly large area lends itself to a little inaccuracy simply because of the difficulty in moving and laying an extremely wet and heavy material like concrete.

When to Use Self Levelling Compound

Using Self levelling compound to get a concrete floor slab level depends on how much it is out of level in the first place. It can only be used if the floor is out of level by 5mm or less. This can be checked in the following way.

Strip off all existing carpets, tiles or other flooring Brush the floor thoroughly removing any carpet tape, carpet gripper, tile adhesive or nails Drop a marble or golf ball in many places on the floor and see which way it rolls to get a picture of where the floor is at its lowest Use a long spirit level to measure exactly how much out of level it is. This should be...
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tools and materials2x4x the length needed to form the edges of the concrete slab Nails, Duplex nails work best because they are more easily removed Steel Stakes to hold the form boards Pencil Level Circular saw Shovel, flat nosed shovel works best to move concrete with Magnesium Trowel Edger Trowel Joint tool, 3/4" for 3 1/2" thick concrete slab

step 1 Determine The Size Of The Shed Floor Concrete Slab

The size of the shed floor area where you intend to lay concrete will determine how the forms are set up and the order in which you pour concrete. If you have a larger shed, like 12x20 or a driveway in front of your shed, you may want to pour the slab in two pours. This allows time to finish the concrete. If the slab you are going to lay has a dimension greater than 10 feet it should have control joints evenly spaced on the shed floor.

step 2 Prepare The Ground

Preparing the ground where you will build the shed concrete floor is...

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You want to lay some rather nice tiles over the unsightly concrete floor in your kitchen, but you know that there's no point in laying good tiles on a surface that's not level, smooth and free of cracks. Good preparation of the concrete is absolutely essential. Before you can think about laying a sub-floor for the tiles, you must deal with the concrete floor [source: Ron Hazelton]. Learn here how to level a concrete floor.

Materials needed:

Latex bonding agentSelf-leveling compoundWaterSandCement

Here's what to do:

Fill any cracks with epoxy. Widen any small cracks, if necessary. Clean the concrete floor as thoroughly as possible with detergent, removing any grease or oil [source: edisoncoatings]. The floor must be dry and free of dust before proceeding.Apply latex bonding compound over all the concrete when the floor is absolutely dry. (This will enable the self-leveling compound to adhere properly.) Use a cheap paint brush to get into the corners and edges. You...
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Whether you are just thinking about a new concrete garage floor or ready to start planning a new one, you probably have a lot of questions. Sure, you might be satisfied to call a concrete contractor and let him tell you what you need. Call several contractors, however, and you are likely to get several different ideas about what you need with just as many different estimates for what it will cost you.

Do Your Research

That's when it pays to do a little research. It always makes sense to understand as much as you can about a home remodeling project, whether you plan to do it yourself or pay someone else to do the work. When searching for contractors, you need to be able to ask good questions and to recognize when the answers you're receiving don't add up.

Lousy concrete slabs are all too common. Slabs that develop cracks are probably the biggest headache, and the folks who pour such slabs are prone to say things like "concrete is always going to crack." Don't...

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Use a level supplied by a hardware store or rent a "builder's automatic level" from a surveyor's supply shop (be sure to inquire as to whether it has been calibrated recently). However, be advised that for outdoor applications of floorings, such as concrete, care must be taken that the flooring slopes to shed water. In other words, an outdoor surface should not be level unless adequate drainage of surface water is otherwise accounted for. Outdoor surface drainage should always positively drain away from your structure. Even if you have a wood deck that drains water between the spacings of the lumber, the ground beneath must shed water in a positive manner away from your building. Depending on the sloop of the land where the pool is going , use a treated 2x4 or larger board as a retaining wall, fill the area where the pool is going with sand and level it. be sure to retain the sand so it does not wash out, and put in some screened holes for drainage Have...

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Photo: shutterstock.com

I’d like some advice on how to level a concrete floor. We plan to finish the basement in my house, and there are going to be a couple of sump pumps, so we no longer need the old drain in the middle of the floor. Thanks!

There is no one way to level a concrete floor. Of all the methods available to do-it-yourselfers, which should you employ? That largely depends on how level you want to make the concrete. And that question, in turn, hinges on a related but different question: What type of flooring do you plan to install in your basement?

If you envision carpeting or another type of floor that forgives minor variations in subfloor grade, such as engineered wood or click-and-lock vinyl, then you can probably opt for the least labor-intensive method. Here, a concrete grinder would do the bulk of the work. (You can rent this tool from your local home center.) You’d use it to grind down the most prominent ridges in the floor. To finish the...

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CONCRETE SLAB CRACK FAQs -CONTENTS: Types of cracks that occur in concrete slabs, shrinkage cracks, settlement cracks, frost heaves. Causes and problems of floor slab cracking; How to repair cracked concrete floors. Slab on grade construction or "patio home" construction cracks; Diagnosing cracks in ceramic tile over concrete slab floors POST a QUESTION or READ FAQs about cracked concrete slabs and floors REFERENCES

InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website.

Floor slab & tile crack diagnosis & repair questions & answers:

FAQs about how to diagnose & repair the different types, sizes, shapes, locations, & patterns of cracks found in concrete floors & slabs. Some floor slab cracks are harmless or even just "cosmetic" while others may spell trouble ahead.

This article series describes the types of cracks that occur in poured concrete slabs or floors and explains the...

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A concrete slab is very useful as it supports not just human footfall but furniture, vehicles and many other items. If you need to pour concrete slab and want to do it fast, a prior experience with concrete is a must. So, if you are a beginner, start small with a sidewalk or a small patch before you pour concrete slab. Once you know how concrete works, you can take up a big project like pouring concrete slab. So, if you are thinking about saving money by trying to DIY pour concrete slab, here is your quick reference guide.

Prepare before you pour slab

You need to have a clear and level ground before starting to pour concrete slab. For this, you can either hire an excavator or do the work yourself. When the ground is clear and level start hop on to the second step to pour slab.

Now, firstly, make sure about your local laws regarding the permit needed to build and how close to build to the road. Once, this is clear you can start with the work of pouring concrete...

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– Old school polishing systems require unfeasible maintenance. Results are illusory by means of diamond tooling contamination transfer, topical sealers and coatings over a ground, fragmented surface.

– Due to the slow economy, the norm is that contractors are undercutting each other and what the client receives at the end of the day is a measured, “shinny” hone sold as a polish, either for bypassing the initial, canvas setting – grind, essential for reflection (as opposed to refraction), skipping steps, or not reaching tool potential, defeating the purpose all together. The outcome are unsustainable surfaces, and sadly, there is a shift back to VCT, toppings, tile, topical sealers and coatings, carpet, etc. At the end of the day, you get what you pay for…or not.

– The ‘proof is in the pudding’ at a recent job illustrations. The first shows shoddy edging; scratches and gouges leading to a rough surface, dull finish. Then on, remaining photos show porosity, damage and...

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Well I finished that job and never got back to the thread.

In the interim I see there's been more than a thousand people look at the thread. So it is of interest. So I'll try to sum up what I did, what I learned.

Right: It is a 4m x 3m steel shed already constructed on concrete footings.

I poured a 100mm slab using my own mixer and a barrow.

I poured it in six different pours.

Dug it out, tamped it down, laid plastic sheet, laid reo in there. Took the reo out under the walls and beyond by 200mm.

Formed it up 200mm wider all around.

Then I cut boards with slots for the reo and divided the inside into two side by side sections at the far end, covering a third of the length.

So I'd have six sections.

The sections about to be poured had reo chairs in them and chairs for a couple of feet on the reo protruding into the section nearer me and that was not yet to be poured but which the barrow would have to run over. And I'd walk...

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If you are interested in what is happening with concrete volumes you can check out the statistics at the Golden Bay Cement website. The March quarter shows volumes running at 917,314 m3 but this is actually the second quarter running that volumes have declined. The biggest quarter was September 2014 at 990,616 m3.

There is no doubt the beginning of 2015 did feel quieter but now we have all been feeling the pressure as the workload builds. We re certainly seeing that here at Conslab. We monitor the area of place and finish work we do by month. This has risen to an incredible 70,000m2 per month. Our record to date has just been set in June with a massive 76,084 m2.Engineers have the best of intentions when they write their specifications but there are clauses, which when viewed against an end user or owners priority list of what is important in a slab, reduce the chance of the slab construction being successful. Conslab believe that specifications should be reviewed from the...

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I am considering building a slab-on-grade, or slab with short perimeter footers, superinsulated house in a cold climate. Most slab insulation schemes I’ve seen put foam insulation under the slab, often with fancy insulation schemes at the slab edge. I very much dislike having a hard, cold concrete floor (and, yes, even a 60*F concrete floor is cold to bare feet). Is there a simple cheap way to make an un-insulated slab with all the insulation placed on top of the slab, then a plywood sub-floor placed on top of the foam? Or maybe 1x6 “floor joists” set directly on the concrete, with insulation (foam, fiberglass, cellulose?) between the joist? Any other...

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