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Flooring and Carpeting/slab/old radiant/old 9x9 tiles


Sick to my stomach with worry and what to do next.We have a concrete/slab levitt ranch with old radiant heat(heat works fine-plumber tested)we recently had laminate put through house, with poor install. Now as the installers were going to redo their mess, they found some cracks in 9x9 tile in bedroom along with moisture.Room has dried out but the crack is still there, plus tiny cracks in the tiles along edges of the room.What is the correct next step the installers don't seem to know.

ANSWER: Thank you for your question Annette,

   Well there are some concerns always with a cracking sub-strate but it is also quite common when a radiant heat source is buried within. You don't mention how big the crack is or how involved (how long it is across the space wall to wall) was it there before or is it new as far as you know? I also am wondering if the 9 x 9 tile is really VCT squares and not Ceramic tile. You didn't say so I'm guessing here. Old cracks are typically settlement cracks that are common in old homes and once settled are usually done moving so no further cracks will arise. So the cracks can be filled with a hydraulic cement that will harden quite quickly and seal the crack from both below (if this is a basement slab) and at the surface. There is going to be more moisture present if this is a basement slab in lieu of a slab on grade or sitting on the surface of the ground basically. As long as the piping for the radiant heating is not leaking or under stress you will be fine in my opinion. The cracking along the edges of the room could simply be if the slab is separate from the foundation wall and has moved over time cracking the tiles, the crack that you see may be that joint beneath. You don't mention what "the mess" is that the installers are redoing, so I have little to go on as a whole to form a concise opinion. The one big thing to look out for is that there is at least a 1/4" space/gap between the end of the laminate and whatever it is laid up to for expansion. That way the floor can breath, expand and contract without buckling and or bowing up in the middle of the room. So clean the floor...fill all cracks with hydraulic cement if they are large enough...(you can use cement caulking if the joint is 1/8" or less just be sure to get it down deep as possible into the crack)...and then monitor the expansion gap at all walls. Ok Annette that's it, I hope this helps you with your problem. Feel free to return anytime...

Perry V.

---------- FOLLOW-UP ----------

QUESTION: The crack is approx 3 ft long-no way of knowing when it got there.When installers ripped up carpet to lay laminate down i wasn't hovering over them to see what they were doing.I believe cracks all around edges of room were created when they got to edges of wall w laminate.Their mess was a poor install, laminate buckling and warping they were here 4 times to fix it before they agreed to reinstall only after independent floor inspector sent by mfr.said it was poorly done.My main concern is if the slab foundation-no basement-Levitt ranch has moisture,radiant heat,then these u put plastic sheeting over it and laminate.Will the moisture sit under plastic creating mold or does it seep back into the tiles? Or is laminate the wrong material to be putting in my home???

Ok...we are getting a better picture here. You have mentioned three times "Levitt Ranch" so I am assuming that this is a particular floor plan?...not sure, but just wondering. So when you are planning to install basically "any" kind of floating material over a cement slab, and in particular a Laminate/pre-finished wood type, the slab should have a moisture test performed just to let you know where you stand and what needs to be done to move forward. Also what Region of the Country you live in also must be considered ie; eastern seaboard or down south along the Atlantic coast line. Heavy rains coupled with high humidity tends to raise the ambient/content moisture level of any formed cement that touches the ground. A Calcium Chloride test might have been done which would have given the "tester" an idea of what they were about to contend with, but that is just one of several that could be done to generate a picture of the whole.

The crack to me in this equation is irrelevent unless there is water leaking out of the radiant system, but still the crack should have been handled just to stall or block any moisture from gaining access to the surface so easily...follow me? Your slab can be painted/sealed with a block filler kind of paint that is more typically used on foundation walls or block to seal and stop moisture from penetrating from contact with the ground outside into the basement, or in your case the slab surface. I reviewed your initial question and did not see mentioned a critical portion of any laminate installation. All of the major laminate/pre-finished manufacturers produce a recommended and matching material to go between the sub-strate and the product called a "cushioned foam underlayment". This is a closed cell thin material that is resistant to moisture when installed correctly and is necessary to isolate the laminate from contact with a potentially moisture filled cement slab. If this was not used at all then you have your answer as to what happened and why. Shaw/Armstrong/Pergo all have a foam requirement that is to be employed beneath their finish product. Laminate is not wrong for your house Annette, it just needs to properly installed and it will be just fine as the material is sold around the World even in the Tropics where humidity and moisture is very high. Once you have a good and dry start mold will not be an issue unless there is a failure which you have already experienced and can easily recognize now right? Ok...I hope this gives you a better understanding of what may have happened and how to better determine what needs to be done going forward to have a successful install and happy outcome. Feel free to return anytime Annette...


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Perry Vellenga


Ceramic Tile/Marble. I can answer questions about floor preparation, tile selection, layout questions, performance of products, expectations of finish, compatabilities, questions about grout and epoxies, evaluating an installer, asking the right questions to check competence...more? 33 years this August 2012/ many years in commercial application from exterior finishes to Mall store fronts/ interior finishes like floor packages in stores inside Malls examples: The Limited, Lerner/NY, Lane Bryants, Bombay Co., Now involved in Residential new construction covering all types of interior finishes and designs.


I worked in an exclusive field of floorcovering called "Tenant Development" which is by invitational bid only, by way of a National bid list. These are large floor packages usually over 3500 sq. ft. of 18" x 18" Marble and Granite and many other types of Marble and sizes. They are specialty stores where the floor package can cost upwards of $50,000 for one store. I have also done "Structure" stores and J. Riggins stores, Lane Bryant,Express and Body Shop stores where wood flooring is used. Presently work for a National Flooring Company in the Residential new construction arena that covers most interior design elements..Granite Slab tops/wood flooring both job finished and prefinished ect..

My response's are published all across the Internet and picked up by multiple Interior Design sites and Industry related web sites where people have questions...

too many most of which don't count...

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