Control joints in concrete basement slab

We are building a house and I have been learning a bit more about concrete lately. You may know the old saying ‘there is only one sure thing with concrete, it WILL crack’. 😉 Of course the trick is getting it to crack where you want to 🙂

‘Control joints’ are cuts made in the concrete so that hopefully when the slab cracks it will follow the pre-made cut. This is the control joint layout that I came up with:

Black lines indicate control joints

Black lines indicate control joints

The idea is to control cracking at the inside corners as well as near the thickened slab portions of the basement.

Please disregard the fisheye distortion in the photo as the foundation is actually square 🙂

Also, here are some articles that I found interesting:

Control joints

Contraction/Control Joints in Concrete Flatwork

Contraction/Control Joints in Concrete Flatwork joints are placed in concrete slabs to control random cracking. A fresh concrete mixture is a fluid, plastic mass that can be molded into virtually any shape, but as the material…
Reinforcement for Crack Width Control |

Reinforcement for Crack Width Control | ForConstructionPros.com reinforcing bars and welded wire reinforcement provide crack width control in nonstructural slabs-on-ground.
Concrete Job Site Technique engineering - When to cut control joints in concrete slab?

Concrete Job Site Technique engineering – When to cut control joints in concrete slab? wet curing for 10 to 14 days, and I mean REALLY wet cure it – put the hose under the polyethylene covering and soak…
When is My Concrete Floor Gonna Quit Cracking? [Archive] – The Garage Journal Board completed a 24×24 detached garage (pictures coming in a later thread..) They poured a monolithic slab the 1st couple of weeks in March. I’m in North Alabama, so they dug the appropriate footer…
No Control Joints in Garage Floor [Archive] – The Garage Journal Board! My contractor neglected to put control joints in our large 3 car garage floor. It’s a large monolithic pour and I’m getting some hairline cracks in various places. The house is almost one year…
Control joints or no control joints ? [Archive] – The Garage Journal Board know most of you guys have recommended using control joints in a new slab, but I’ve also noted some that have no joints and no cracks. Currently I’m getting ready to pour a 27 x 57 slab @ 6″…


Chemical Admixtures

Chemical Admixtures admixtures, which slow the setting rate of concrete, are used to counteract the accelerating effect of hot weather on concrete setting. High temperatures often cause an increased rate of…

Superplasticizers, also known as plasticizers or high-range water reducers (HRWR), reduce water content by 12 to 30 percent and can be added to concrete with a low-to-normal slump and water-cement ratio to make high-slump flowing concrete. Flowing concrete is a highly fluid but workable concrete that can be placed with little or no vibration or compaction. The effect of superplasticizers lasts only 30 to 60 minutes, depending on the brand and dosage rate, and is followed by a rapid loss in workability. As a result of the slump loss, superplasticizers are usually added to concrete at the jobsite.”

Concrete Additives

Concrete Additives Sealer Seal Pro MS300 is a clear deep penetrating, non-yellowing solvent base sealer designed for concrete substrates. It protects and preserves as a surface hardener, dust proofing agent…

Radiant Heating Tubing (PEX etc.) and Control Joints

Control joints after pouring concrete over the PEX tubes is a good and secure method to have control joints made in concrete that was poured over PEX tubes for radiant floor heating? How can…
Contraction Joints for Radiant-Heated Floors |

Contraction Joints for Radiant-Heated Floors | ForConstructionPros.com saw-cut contraction joints in radiant-heated floors is similar to standard slab-on-ground floors except placing and maintaining reinforcement and tubing locations are critical. Otherwise,…


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