DIY How to Install a Basement Subfloor



so a lot of us in the building industry we've come across this dimple in plastic before it's called plateau but the reality is it's not the product name that's just a product brand name so this is actually DMX this is available my local building store I picked it up I usually use this for my sub floors underneath the five-eighths tongue-and-groove OSB plywood and we can screw that to the floor with tapcon screws and that's my traditional basement system but what I was curious about was this little thing right here so this is another product same company DMX it's blue it's a three and one so this is insulated it's a vapor barrier and it's soft and cushiony so you can actually make your subfloor out of this and laminate right over top they've gone through the trouble of testing it and getting it approved for putting a laminate floor directly on this product I'm not a big fan of that especially in this installation because I'm building interior walls and I don't want to be setting walls on this and I don't want to be building my walls first everywhere and then filling all my cavity with this because I'm on a walkout and we have this for season whether we run the risk of a thaw freezing cycle and getting moisture underneath our concrete pourer and if that happens I want to have an airspace that transfer that moisture past all my interior walls and let the building soak all that up over time if I build my walls first and put this down I'm going to be trapping moisture and I'm going to get that musty smell no matter what I do so this is a good product if you're just doing one room and you already have walls but if you're like us and you're building new walls go with this system the funny thing is they're both plastic and at the end of the date the same cost per square foot to install this and plywood or this alone so it really comes down to what's more convenient for you and your situation but I would recommend both these products they both work great there we go just easier for us to do the layout this way a little longer than I need the best part we're doing the same thing again the other side of the roof so you can see that what we just put down here is square footage-wise is almost 400 square feet took about 10 minutes which is awesome we tape it together with a new blue tuck tape this stuff is the same as a red only it has been tested and approved for wet areas so this will hold on classic the plastic even when it gets wet so now we have this whole areas one vapor barrier which is brilliant you'll never get that if you use dry core traditionally when you're laying down flooring you'd use the square like this measuring tape and you're basically working off of whatever is pre-existing now we all know we never find anything square in a house so what we're going to do is we're going to use the laser level techniques and you can see I got it lined up right now and this line here represents a straight line from one steel post to the other and we're going to use this to establish our square for the entire project this way we're going to build wall off of each of these areas we're going to start everything off square on that line because when you're building if you have one thing that's always going to be straight and square and everything's built off of it the rest of the project moves so much faster [Applause] what we've done is we've marked our laser line and our laser line is going from post to post and it's off this point here so we cut our plywood from our end wall to fit our frame for the door plus three inches and then we've also cut a plywood cluster right here and a little extra half-inch that's because when I put these doors in the door will go here they'll be hinged open and when it's closed the middle of my door will be over the transition of the one floor into the next I'm going to go from laminate to tile so by doing this in advance it just makes my life easier all aware one two and then three so we're done drilling a few holes just to do a little demonstration for you how we secure this to the floor that's an SDS machine it's awesome it's a really good hammer drill you can see there wasn't a whole lot of effort going in didn't have to put his body weight behind it if you have one of these drills you can actually switch this gear over to hammer it will work it'll take five times as long it'll get the job done but if you're doing a big space like this and you don't own one like this let's go to the store and rent it twenty-five bucks for the day definitely worth the investment we're using tapcon screws coated screw won't rust pull in everything nice and tight even though we probably tight or maintaining our airspace underneath the plywood it doesn't have to be a lot because any air that's moving will take any moisture that could possibly get underneath this floor someday and it'll transfer that all through the house and it will stay dry forever and you'll never have a moisture mold mildew kind of problem so you can see so the system works great we need about six or eight screws for every sheet of plywood because it's clung and grew if I put a screw within a foot of that joint I'm also compressing the other sheet so you don't have to go a lot of overkill just make sure that when you're walking around you got rid of a spongy spot if you need to put a few extra screws somewhere that's fine also while you're drilling you might notice where you are you might have softer concrete and depending on the driller you use when you're drilling your hole if your screws aren't grabbing then just make one little change drill straight through don't clean the hole as you go sometimes the concrete can be a little bit too soft so if you just push down and leave all that dirt in the hole then you'll have something there to bind that screw to the hole and it won't be lifting out on it if you're enjoying these videos subscribe to the channel hit the like button the most importantly comment on the video by all means or a suggestion of video you'd like to see let us know we'd love to be in touch

24 Comments

  • Arjun Chopra

    April 14, 2019

    Hi, great video. One question though, my basement is a big hall with concrete floor and I want to erect walls. Should lay the black dmx, plywood and then the wall or lay the base of the wall on the concrete first and then use dmx +plywood in each cavity?

    Reply
  • Nazmus Saquib

    April 14, 2019

    Is this floor you have installed 'insulated '? How would you make it insulated?

    Reply
  • Boe Dillard

    April 14, 2019

    I don't think I understood why one traps moisture and the other doesn't if you do everything else the exact same way.

    Reply
  • James Reeves

    April 14, 2019

    What if say water heater burst and allotbof water gets under flooring you put down

    Reply
  • Penguin1290

    April 14, 2019

    Can you show how you do the transition from this subfloor to the area you talked about that was going to be tile?? How do you make sure everything matches up so you don't have a step down or up?
    In my basement I want to use this DMX/subfloor system under carpet – and I will have a bathroom with tile adjacent to this.

    Reply
  • tdot22

    April 14, 2019

    Do you need this if you’re going to be laying down tile?

    Reply
  • dmitrynikgt

    April 14, 2019

    Hi Jeff, Few Questions :
    1.Some people recommend to install eps rigid foam instead of dimple mat to prevent hot humid air reach cold condensing slab (climate zone 3A) . Some say top of dimple mat will become condensing surface as it will be near slab temperature. Your thought?

    2. Delta MS recommends to seal the dimple mat around perimeter walls. Where would moisture escape to to dry? Does dimple mat have any perm rating at all?

    Thanks

    Reply
  • Ryan Gorley

    April 14, 2019

    Thanks so much for the video. Do you recommend acclimating the OSB before screwing it down?

    Reply
  • Craig Raypold

    April 14, 2019

    what length of Tapcon fastener did you use for this installation?

    Reply
  • Richard Lahti

    April 14, 2019

    I used DMX One (the red product) across my entire basement floor and built the partition walls on top of it. It was approved by the local inspector as gasket to separate the wood from the concrete in the walls. It has an 8000+ PSI rating which is better than the drycore and as evidence to its robustness, I built a temporary support wall on it for a week while restating and it didn’t deform as a result. I figure I also saved about an inch in room height, and laminate feels solid over it

    Reply
  • Dan Dan

    April 14, 2019

    Aren’t you concerned that, given a leaky slab (water eventually comes up through small cracks) the screws will allow that water to soak the OSB?

    Reply
  • ianteniedo

    April 14, 2019

    Glad I found a Canadian reno channel, really love your videos, very informative. I think it would be also great if you could incorporate tips (maybe inserts) on codes e.g. building, fire, plumbing, etc (could be international, national (Canada), or provincial)in your videos so DIYers who doesn't know this yet will learn what are the recommendations and requirements. Thanks Jeff, looking forward on more videos!

    Reply
  • Joe Sciullo

    April 14, 2019

    The manufacturer claims that off gassing can occur with the dmx ag product you are using here. It is foundation wrap meant for outdoors. It is not made from virgin resin. It has warning labels on it now for outdoor use only. Thoughts? Thanks

    Reply
  • Jmaclicious

    April 14, 2019

    I plan to use DMX Airflow on my basement floor, I did try to self level a bit of my basement mainly the areas that were super dipped from an old floor drain/laundry room that once was there and relocated. However DMX states the floor should be level to 1/8 over a 10' span… pretty difficult to do, I got the occasional dip around 1/4 maybe 3/8" here and there, I do plan on using carpet as well.. do you think being a roll out membrane it will contour to the ground or will I feel it squish/bounce every time i walk over those dips? I love your vids!

    Reply
  • Kyle uses his brain

    April 14, 2019

    2:08 That's what she said.

    Reply
  • kyle kelly

    April 14, 2019

    My wife and I bought a house. We live in a four season area. Our basement is unfinished but has all the studs placed in. We do get water or moisture when the snow and ice melts. We want to put a floor in our basement, but are scared if the water would cause mold or we would have to replace the flooring every few years. Any suggestions on how to do an elevated floor or a way so that the water wouldn't cause any or minimal damage to our home.?

    Reply
  • Iris Gilmore

    April 14, 2019

    Not helping

    Reply
  • Simon Gauthier

    April 14, 2019

    What’s the maximum slope of the slab that you allow?

    Reply
  • Brent Toombs

    April 14, 2019

    Awesome video! If a basement is completely empty with no perimeter walls built, can the membrane and T&G subfloor extend just short of the block wall, and then build perimeter walls?

    Reply
  • Vova *******

    April 14, 2019

    Heard some people been installing laminate or vinyl planks over top of the DMX. would you recommend doing that or should I install some OSB over top . Thanks

    Reply
  • ClubbersGuideCanada

    April 14, 2019

    You mentioned that building the walls after installing the membrane and 5/8 t&g plywood is best. I’m assuming the exterior walls were already done prior to your involvement? Is t&g necessary or would non work?

    Reply
  • Jason Bellanti

    April 14, 2019

    So if I am looking to build a room in my basement I am okay to install the subflooring with dmx and plywood and build the walls on top of it? Sorry just want to make sure I am understanding that correctly.

    Reply
  • Grease Medic

    April 14, 2019

    What are thoughts on tile or epoxy floors in a basement? I Will be finishing my basement this summer and have watched a ton of your videos. Great Info!

    Reply
  • shawn l

    April 14, 2019

    Would it not be better to glue the sheets together instead of breaking the vapor barrier with a screw ?

    Reply

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