Your home and family deserve the best – choose DMX 1-STEP, the new standard in flooring underlayment. DMX 1-STEP space-age contoured foam and unique dimple design provides the ultimate in sound absorption while allowing air to circulate beneath your floors, evaporating trapped moisture and eliminating harmful mold growth. Installation is simple and fast – no special tools required.
Roll Length27.5 feet8.38 metres
Roll Width44 inches 1.12 metres
Dimple Height 5/16"8 mm
Roll Weight15 lbs6.8 kg
Sq. Ft. / Roll100 sq.ft.9.38 sq.m.
Available At

Just the Facts …

  • DMX 1-Step underlayment is 3 in 1 protection – vapour , air AND sound
  • The best choice for Laminate or Engineered Hardwood over concrete or wood subfloors
  • Makes your flooring warmer to live on with the added peace of mind of moisture & mold protection
  • Only dimpled underlayment certified by North American Laminate Floor Association nalfa
  • 50-year Warranty – most comprehensive warranty in the business
  • Completely waterproof on both sides
  • DMX 1-Step does not require a complicated Calcium Chloride test of the concrete slab like foam underlayments
  • Compressive strength 6,000 lbs/sq.ft. or 43 PSI

What is DMX 1-Step™?


The New Standard In Underlayment

WHISPER QUIETSpace-age contoured foam designed to absorb noise and vibration.DMX 1-Step™ has a state-of-the-art design that provides you with the ultimate in sound absorption and cushioning of your floors, absorbing sound and reducing noise.
DIMPLE DESIGNTough HDPE membrane with unique dimple design doesn't trap moisture like traditional foam underlayments.DMX 1-Step™ has an air-gap dimple design that allows damp concrete to breathe and provides room for moisture to evaporate, ensuring your flooring stays dry, warm, and comfortable.
MOLD BARRIERAir flow and air circulation beneath your finished floors allows moisture to evaporate. No moisture = No mold.DMX 1-Step™ has a unique air-flow design that allows for air circulation under your floors, evaporating trapped moisture and eliminating harmful mold growth, which means a healthier environment for your family.
R-Value of 0.91*
The R-Value measures the level of effectiveness of insulating materials and how well your home is protected from heat loss.DMX 1-Step™ has an R-value of 0.91, ensuring that your floors will be kept warm in the winter, minimizing costly heat loss and giving your family the ultimate comfort.

DMX 1-Step™ is the ONLY dimpled underlayment certified by the North American Laminate Flooring Association, and the ONLY underlayment to offer a 50-year warranty.The highly durable construction of DMX 1-Step™ outperforms all other flooring underlayment, providing years of long-lasting quality, durability, and peace of mind.



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Product Comparison

 DMX 1-Step™ Underlayment
A Roll of DMX 1-Step™
Roll of FloorMuffler
Panels of Dricore™
Approved by North American Laminate Floor AssociationNALFA LogoYes!No!No!
Airflow Design To Evaporate Moisture From ConcreteYes!No!Yes!
Moisture-Proof Seal At JointsYes!Yes!No!
Water-Proof On All SidesYes!Yes!No!
Manufacturer Requires Anhydrous Calcium Chloride Test Prior To Installation On Concrete (ASTM F 1869-04)Not RequiredRequiredNot Required
Manufacturer Specifies a Maximum Concrete Moisture Emission RateNo Limit3lbs/1000sq.ft/24hr***No Limit
Compressive Strength ASTM D 16216,000lb/sq.ft**Not Published4,000lb/sq.ft***
STC (Sound) Rating / IIC Rating66**/69**Not PublishedNot Published
Warranty50 yearsLimited Lifetime25 years
Price*$0.72 per square foot.$0.65/sq.ft.$1.60 per square foot.
*Information obtained on Nov 21, 2015, as per retail pricing at a major coast-to-coast, big-box retailer. Information may vary from area to area. Prices in Canadian Dollars.

**Numbers based on laboratory testing.

***Numbers retrieved from the manufacturer’s web site.


FAQ’s for Installing Laminate Flooring with DMX 1-Step

1. If I am laying laminate flooring how thick does it have to be?
We require an 8mm minimum thickness of laminate when installing on 1-Step™.

If you use a thinner laminate product we suggest the use of a 5/8″ T&G OSB over the 1-Step™ first to provide these benefits. If there is too much deflection in the laminate this could compromise the snap lock mechanism of the laminate, and void your laminate warranty.

Check with your laminate floor manufacturer on their limits of deflection for the specific floor you are installing.

2. Do I need to lay an OSB subfloor on top of DMX 1-Step™?
Floating floors that include a click-type mechanism for connecting the pieces together can be used without the solid subfloor. These floors are considered floating floors and providing they are at least 8mm thick there is no need for OSB.

Floors like solid hardwood, and some engineered hardwood are nail down floors. If you are installing a nail down floor, then you DO require an OSB subfloor on top of DMX 1-Step™ because the nails need to be secured into a solid substrate.

3. Do I need to install a foam underlayment on top of DMX 1-Step™ before laying laminate or engineered floors?
DMX 1-Step™ DOES NOT require a foam underlayment to be laid between it and the laminate/engineered floor. However, this is completely optional, you may do it if you wish.

4. I plan on using your DMX 1-Step™ underlayment for a 12mm laminate floor. Would I gain any benefits from putting down an underpad layer of cork between the DMX and the laminate? Or would that be overkill and unnecessary?
The use of a layer of cork underpad between the DMX 1-Step™ and the laminate flooring will provide some increase of thermal performance since cork provides some thermal breaking properties and the total overall mass of the assembly will be increased. It will also increase the acoustic benefits of the floor assembly (especially if over another area where there is living space below), but for normal basement use is not required to be installed for acoustic purposes.

The installation of the cork will not affect the performance of the 1-Step™, nor the laminate.

5. Can the 1-Step™ with 15 mm laminate over support a pool table placed on it?
The 15 mm laminate material should be thick enough to handle the load from a typical pool table, however you should check with the manufacturer of the laminate to ensure that the “click lock” system will also handle it. The 1-Step™ with this thickness of laminate will handle the load, as well, without issue.

FAQ’s For Installing OSB with DMX 1-Step
1. How do I seal the holes that are drilled during installation of OSB subfloor?
When you pre-drill the holes in the OSB subfloor use Tap Con screws. Prior to driving the screws into the concrete dip each screw into a polyurethane sealant before inserting the fastener into the bottom plates of the wall. Since the Tap Con screws have two different threads (a cutting and tracer thread) the sealant will be deposited on the membrane as it goes through. This helps maintain the vapor barrier that has been penetrated by the fastener.

2. I have 3/4” engineered hardwood to put over top. Do I need to still place the 1/8 foam sheet over your product and under the hardwood?
You do not need to install the foam over the 1-Step™. You will need however to install 1/4″ thick shims along the perimeter of the walls to provide the air space needed for expansion of the wood and ventilation. The shims can be made from any non wood product, such as plastic or fiberglass, to match the height of the final floor elevation.

3. I understand that I need to apply a 5/8″ tongue & groove OSB/Plywood over the 1-Step™ first for other types of LVP. Do I need to glue or nail the OSB/Plywood to the 1-Step™? If so, what kind of adhesive do you recommend?
The installation of the OSB/Plywood would not need to be glued at all. The OSB/Plywood is screwed to the floor to form a solid subfloor.

FAQ’s For Installing Radiant Floors with DMX 1-Step
1. Can I install radiant heated floor mats over the 1-Step™ when installing laminate flooring?
Go for it! I looked at the web site and the felt type pad that separates the heating coils from making direct contact with the 1-Step™ is ideal. Good luck with your project, should you have any additional questions please get back to us.

FAQ’s For Leveling the Floor with DMX 1-Step
1. If by chance my basement isn’t leveled properly (I haven’t actually taken note to see it is or isn’t) how would I go about leveling this above the concrete?

To level the top side of the concrete slab, using a string line from corner to corner of the areas to be checked, stretch it along the surface of the concrete slab and check to see where the high and low spots are on the slab. Using a 48″ bubble level check the differential between the high and low areas to see if they are in the range of 3mm over a 3m span, which is about 1/8″ over 10′. If so this is acceptable. Also check to see that the slope or differential runs in a single direction (and example would be from side to side or end to end of a room).

Any areas not within this limit of slope should have a self leveling cementitious coating put over the low areas to bring them into the range as specified or true level. The more level the floor surface the better the finished installation will be, and your experience will be more positive. When considering laminate or engineered hardwood floating floors it is especially important to get the floors as level as possible since even a 10 mm thick laminate floor will have deflection in it which can be accentuated with an uneven floor.

There should be no high and low spots spread randomly throughout the floor area, this can lead to movement issues in the 1-Step™ and the laminate or engineered hardwood. Perfection is great, but since that is not usually possible the level on the slab should be such that the slopes in the floor are consistent in terms of direction (side to side or end to end) and within the tolerance mention above.

FAQ’s For Finished/Unfinished Basements with DMX 1-Step
1. How do I install non-load bearing walls on top of DMX 1-Step™?
There are 3 scenarios for installing DMX 1-Step™ under non load bearing walls:

Scenario 1: If the basement area is open without any exterior walls installed, you can take DMX 1-Step™ to the concrete walls. You can seal the open joint between DMX 1-Step™ and the foundation wall using a limited expansion polyurethane foam (from the can). Once this is done, you can build your walls on top of DMX 1-Step™. The only drawback to this situation is that the weight of the wall, if too close to the seal, may break the seal made with the foam. This can lead to vapor moisture getting behind the stud wall, which if great enough could cause condensation and mold/mildew to grow on the wood studs.

Scenario 2: An alternative to (1) is to take DMX 1-Step™ to the concrete wall, bend the membrane so that 1 dimple is travelling up the wall face, and seal the void created by the dimples of DMX 1-Step™ with the spray foam. This provides a complete protection system for your wood stud bottom plate, and puts the seam created out of harm’s way. Any weight distribution will be on the membrane in the horizontal plane, and not affect the vertical turn up section. The foam should be installed to seal the void after you get the stud walls installed, prior to insulation and drywall, and the extension that comes with the foam can be used to reach the area behind each stud. Leave a small opening (1″) every ten feet so, in both cases, so any water that leaks from the foundation wall has a chance to drain to the outlet provided and drain under DMX 1-Step™.

Scenario 3: If you install the stud walls first, then install DMX 1-Step™ you need to leave a 1/4″ space around the perimeter of the room (from the drywall) for ventilation, and leave the baseboards up 1/8″ off the finished floor. This scenario does not require you to seal the perimeter, but the spaces are required.

2. In your installation video, you suggest leaving a 1/4 inch gap on the edge for the walls for drywall and trims. If my basement is already finished (minus the trims), can I butt the DMX right against the wall?
Based on the situation you have described, you should leave the 1/4″ gap between the 1-Step™ and any finished flooring above. Once you have completed this you can reinstall the trim, which usually are about 1/2″ thick, which will hide the gap, however you need to leave the bottom of the trim up off the finished floor 1/8″ so that ventilation still takes place.

The fact that the drywall and wood stud walls are constructed to the floor, if you close off this material below the 1-Step™ you run the risk of mold or mildew forming on these organic materials. This also helps account for any small amounts of moisture that find its way onto the floor from cracks in the foundation walls, by allowing it to dry up and keep this area from accumulating excess moisture and supporting mold.

3. I have a basement with finished up to the drywall stage and want to replace my carpet. What are the options to install 1-Step™ and laminate flooring?
There are a couple of methods to install the 1-Step™ in this circumstance:

Installing the 1-Step™ over the entire slab area leaving a 1/4″ gap around the perimeter of the room to allow for expansion of the flooring materials, and allow vapour moisture to escape only at the perimeter so that moisture does not form and create mold or mildew on the wood framing and drywall.

Installing the 1-Step™ is the same as above, and extend the polyethylene that was placed under the bottom of plate of the stud wall so that it rests on top of the 1-Step™, then taping the polyethylene to the 1-Step™ using the 1-Step™ tape.

The installation method shown in the drawing on the DMX site is for a condition where the exterior walls have not been drywalled or insulated, and does not apply to your case. However if you remove the bottom section of the wall assembly you could use the details in this drawing, you would have to evaluation the cost differential before ensuing this course of action.

4. Can I build wall partitions on top of the 1-Step™?
You can build “non-loadbearing” wall partitions on top of the 1-Step™ without issue. You must however seal the penetrations made by the fastening method for the bottom plates using a butyl rubber or polyurethane sealant prior to installing the fasteners. Check our FAQ section for more detailed descriptions on this process.

5. Do I need to seal the perimeter of my 1-Step™ installation? If yes why and how? What alternatives are there if I don’t have polyethylene under the wall plates?
The purpose of the gap when existing walls are present is so that vapor moisture isn’t trapped where there is organic material (wood) which could become wet/damp and support mold and mildew growth without the use of the air flow in the gap area. Along the perimeter walls this ventilation is especially important when water seepage through the exterior concrete foundation walls can contribute to the accumulation of moisture in the wood materials. Sealing them with foam without providing any outlet for the seepage water to flow under the bottom plates, and protecting the wood material from direct water exposure, can contribute to mold and mildew formation. Protecting the wood elements from supporting mold and mildew or providing for the drying effect to dissipate any moisture and keeping the wood elements dry has a direct impact on your interior air quality. If you want to foam the existing plates it is suggested that you drill holes into the existing bottom plates and pour in some wood treatment (green or bluish green in color) into the holes to coat the underside of the existing bottom plates, paint all sides the bottom plates as well on the exterior faces which will provide some protection from direct contact moisture damage and mold and mildew formation. Let this treatment soak into the wood, and reapply a couple of coats. As this is not a normal case which we frequently address, thus we have not included it in our FAQ section, however this method has worked in the past without issue by other customers with similar circumstances. When you foam between the bottom plates and the 1-Step™, leave an opening in the foam of about 1″ in length every 10′ so that seepage water can get out from behind the bottom plates and drain to the floor drain or sump pit. You can use the DMX seam tape to seal over the gap by attaching it to the 1-Step™ and the bottom plate, extending the tape 12″ each side of the drainage opening. An alternate detail would be to take (if it is in place) any polyethylene that was originally placed under the bottom plates of the walls, and extend it up to the top of the 1-Step™, and tape it to the 1-Step™. This will also provide a vapor seal along the existing partitions. When addressing special circumstances such as yours there is no “sure fire” method to deal with the integration of moisture protection while leaving the existing construction in place. A combination of methods is often used to achieve a best approach to the situation. Beyond this the only alternative is to cut out the lower portion of the existing construction and replace it with construction methods and materials which allow you to complete the work continuously in the same fashion throughout, which can become very costly. When existing construction is in place it makes it more difficult to stay the course with a particular detail which assumes that the physical state of the area being completed is to the contrary, so special circumstances may apply, as in this case.

General Questions About DMX 1-Step
1. If you leave a 1/4″ gap along the perimeter of the room to allow moisture to, could that moisture not get in to the drywall and stud wall?
There are several things at play here, and you first need to know (or ask) what construction type that was done for the walls, drywall and insulation. The bottom plates of the walls should either be pressure treated or have moisture protection placed under them when in contact with the ground or concrete (in this case the slab), and it can take to form of either poly or tar paper. The vapour barrier over insulation should be behind the drywall and sealed. If neither of the above have been done then not matter if they leave a 1/4″ gap or not, vapour moisture will attack the wood bottom plate and suck that moisture up into the stud wall (about 2″ or 3″ up into the stud). As for the drywall the only time that moisture will create a problem with drywall is if it gets wet from either condensation or leakage water (albeit foundation or plumbing in nature) and will retain that moisture for some time. The paper on the drywall is (like the wood) an organic product which will support mold and mildew growth when the 3 conditions are met which can support this propagation. The air gap provides a way for water and vapour moisture to exit in a controlled manner from the interface of the horizontal plane (floor) and the vertical plane (the wall) and not accumulate to a point where it can cause condensation (the form of moisture that is immediately detrimental to drywall and wood). By bleeding off this vapour moisture (even in the case where there is a leak, the evaporation of the water turns to gaseous form first [vapour] then escapes to the leaner air mixture in the room area where it is absorbed and evacuated through door and window seals and any air exchange that happens in an area due to fans. An important note here is that the bottom of the base board must be left up off the finished floor finish 1/8″ to allow this air flow to be continuous, otherwise you will be cutting off the air flow and the moisture will accumulate at the wall line. There are instances where if the construction of the walls allows the poly under the bottom plates can be placed on top of the 1-Step™ and sealed to the 1-Step™ via tape creating a continuous vapour barrier around the perimeter where the 1.4″ gap is not required. This is not always the case and not what I have found most DIY or builders do in the majority of cases, and to try to correct this after the fact is next to impossible without much more work involved..

2. I have a frosty coating on my basement walls during the cold months, will 1-Step™ help, what causes this?
Improper installation of the vapour barrier over the insulation and stud wall assembly allowing vapour moisture to collect behind on the concrete walls. Wet lumber used at the time of installing the exterior stud walls, which in a basement environment can take longer than normal to dry out. Electrical plugs on the exterior walls were not properly sealed at the vapour barrier, allowing moist air from the living space to enter into the wall assembly thereby collecting on the concrete walls and freezing. Ineffective sealing of the perimeter rim joist and sill plates, and any penetrations for plumbing, HVAC, and vents which allows cold air to draft into the wall cavity, and in some cases allow damp air from the exterior to condensation on the interior face of the concrete walls in the vacinity of the penetration. These items should be checked to ensure that moist air is not collecting behind the wall cavity. Also check for intermittent small leaks in the walls (easier said than done, but a possibility especially considering the amount of moisture in soil after a winter freeze and the spring thaw). 1-Step™ will keep your finished floor above the liquid moisture line under the circumstances which you described and protect the finished flooring materials from liquid moisture damage

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