I'm using Pressure treated lumber for the bottom plate in a basement finishing project.

  • What should I use to seperate the wood from the concrete?

  • What are ways to secure the bottom plate to the floor?

  • I wrote an answer but just noticed the 'floating floor' part. Are you wanting to attach your baseplate to the concrete, or a floating floor? If the latter, what kind of floor are we talking about?
    – DA01
    Commented Feb 17, 2012 at 20:13

4 Answers 4


Pressure treated "PT" lumber is made for damp areas, where there's moisture and direct contact to concrete or earth. Make sure to use the proper coated anchors for Pressure treated lumber. such as hot-dipped galvanized or stainless steel fasteners. there's more detail about this below.. keep in mind pressure treated is not only a preservative it is also a poison to prevent termites..

An alternative you can consider using fir or pine as your bottom plates, if on concrete you can't have direct contact. lumber will take the moisture from concrete and either cause dry rot. To prevent that from happening lay down sill gasket a foam like material in a roll.. made for this reason.. and can be found in most home hardware locations..

Commencing in early 2004, the pressure treated wood industry ceased producing CCA treated wood for many residential uses. A number of replacements have been developed including Copper Azole (CA), Alkaline Copper Quaternary (ACQ) and Sodium Borate (SBX).

With the change, ACQ and CA will almost certainly be the preservatives used in generically designated “pressure treated” sawn lumber in use in building construction. SBX treated lumber is available but would need to be specified as such.

Practices and customs that were adequate with CCA treated lumber may not be appropriate for use with the new products.

Some of these “next generation” wood preservatives are significantly more corrosive to metal than was CCA treated wood. Current information suggests that this increase in corrosion particularly applies to CA (and ACQ but not to SBX)

The use of hot-dipped galvanized or stainless steel fasteners with the pressure treated wood, and avoidance of contact of aluminum with pressure treated wood have been long standing recommendations; although, in practice,these have frequently been overlooked with no serious consequences (other than pitted aluminum flashings). With the new preservatives these recommendations should no longer be ignored. Thus it is important to specify and obtain appropriate corrosion resistant materials to ensure adequate service life for fasteners and connectors.

Aluminum should not be used in contact with pressure treated wood. Spacer materials or other physical barriers are recommended to prevent direct contact of pressure treated wood with aluminum products.

I realize this is an old post but i hope this information helps people looking for the right answers. if you would like help with anything else look up my page up on facebook- RCM Construction


I'd strongly encourage you to consider metal studs instead of wood for a basement finishing project. There are many reasons. I've outlined my conclusion in this question:

Should I use steel or wood studs for basement exterior walls?

Either way, though, yes, you want to separate the base plate from the bare concrete. With wood, you want something impermeable to water. I'd suggest the rubber window-wrap product for that. For metal, I used very thin pink XPS foam board to act as a bit of a thermal barrier.

As for how to attach it, this is the fun part. You get to go buy a powder actuated hammer!

A powder actuated hammer is basically a rifle. You load it with .22 caliber shots that then shoot a nail through the wood into the concrete.

There are two main types of them. One is like a chisel, and you strike the top place with a mallet to fire the shot. The other looks more like an actual rifle with a hand trigger. I've used both and will say that you will save a ton of time/headaches by paying the extra $10 for the trigger based one. Wear hearing/eye protection!

  • 5
    For a little extra safety, don't stand with your legs on either side of the gun when you use it - stand to one side. The foreman at the construction company I worked with one summer told me that freak ricochets rarely (but do) happen. Better to have the nail glance into your calf than other more 'sensitive' areas. He may have just been trying to scare the new kid, but I took his advice anyway.
    – Doresoom
    Commented Feb 17, 2012 at 20:00
  • @Doresoom, I'm wincing thinking about that. Commented Feb 18, 2012 at 0:04
  • 1
    Sill Plate Gasket (though you might get moisture infiltration through the nail holes).
    – Tester101
    Commented Mar 21, 2012 at 20:35
  • 2
    I've rolled back edits. I don't consider recommendations for alternative and potentially better materials 'superflous'. Someone also added a bunch of typos. I will update to use the term 'powder actuated' though. Looks like both power and powder are terms uses, but powder definitely seems to be the more common.
    – DA01
    Commented Mar 21, 2012 at 20:45
  • 3
    You are free to disagree, but the answers here aren't just for you. They're for any potential person looking for answers. And I think in many subject matters, such as home construction, it's important to inform people of options they may not have considered. I still see a lot of bad basement finishing jobs due to out dated information. I'm not saying wood is the wrong choice in your situation, but it often is in a lot of situations and people should be aware of the pros and cons.
    – DA01
    Commented Mar 21, 2012 at 21:16

Another way of attachment is to use the blue Tapcon screws. A hammer drill, hex drill bit, and masonry drill bit(s) are required. I used these on my basement and it was pretty easy (but noisy).

I've used the ramset gun (actuated hammer) in the past and I can say the gun is more fun and perhaps easier. Although it makes my significant other very nervous when it is used (sounds just like a gun). Just be aware there are different shot loads (they are color coded) yellow, green, etc. and one will need to find the load to drive the nail through your concrete. Do a few test shots first.

If you want to build up your forearms, you can go old school with concrete spikes and a small sledge hammer well.

Please note I have no affiliation to Tapcon other than using the screws on a project.

  • 6
    "sounds just like a gun" = because it is a gun. ;)
    – DA01
    Commented Mar 21, 2012 at 20:48
  • 1
    Concrete spikes (we called them cut nails) are easy/cheap if you don't have a lot of tools. But do take care to wear eye protection, they can shatter when hit the wrong way. You can even install them with a hammer, and a lot of effort.
    – BMitch
    Commented Mar 22, 2012 at 1:35

Use something impermeable to water to separate the wood from the concrete.

  1. Window/Door Flashing tape
  2. Sill Gasket

Possibilities for securing the wood framing to the floor:

  1. Powder Actuated Hammer - a tool which fires a .22 caliber shell loaded with a nail.
  2. Tapcon Screws - Pre-drill base plate and concrete and then secure to the floor with Tapcon screwes. This will require a hefty hammer-drill. A cordless may drain too quickly depending on how much framing needs to be secured to the floor.
  • Liquid nail won't help if you've separated the stud from the floor with a barrier of some kind.
    – BMitch
    Commented Mar 22, 2012 at 1:32
  • After an earthquake in California, where house frames that were not secured to the cement footing slid off their foundation, it was a good business to secure the frame with giant (1-2' long, 1" thick) steel screws that we then glued in with cement glue. Forget the actual product names. Also check the code, not sure if where you are is prone to earthquakes, but you want these spaced a certain distance apart.
    – michaelok
    Commented Apr 4, 2018 at 16:05

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