Finishing Safe Room

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Old 12-10-19, 01:46 PM
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Finishing Safe Room

Hello all!

I have a safe room that I'd like to finish this winter. It is located under my front porch. It has poured concrete walls and a steel corrugated ceiling. I have two access holes to bring in electrical and air supply so that is not an issue.

My question is in regards to general framing. Should I use 2x4s or 2x3s? Do I need to insulate the space or install a vapor barrier?

I'd like to be able to tile the concrete floor and then use leftover white oak tongue and groove flooring as sort of a wainscotting and then start with grooved paneling or something to mount guns and tools on.

Any direction to go would be great!

Rick
 
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Old 12-10-19, 01:58 PM
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What I have seen in most rooms of that type is that they are cold, underinsulated, and lack conditioned air. As a result they have moisture (condensation) and mold problems.

Basically what I would recommend would be similar to how many basements in the northern US and Canada are insulated. At least 2" of high density foam applied directly to the foundation walls, air sealed on all edges and seams, applied to the ceiling and walls. Then 2x4 walls with insulation are built next to the exterior walls but no interior vapor barrier. Assuming the floor has been insulated under the cement pad, it should be warm enough to be tiled as is.

Then you'd just want to make sure you are providing heat and ventilation to that space.
 
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Old 12-10-19, 02:18 PM
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I have one air vent coming into the room from my HVAC. I know that I will need to get a dehumidifier just in case to prevent too much moisture with guns and tools being in there.

I don't think the concrete floor was insulated underneath. To my knowledge they had a vapor barrier and stone with the steel mesh and just poured the concrete. I suppose I could lay down an electric heated floor mat under the tile but it's not like I will spend a lot of time in there. It's just a place to store my guns and other valuables and a place to go to in case of tornado or major hurricane. I could probably throw a space heater in there if I needed it. Heck, I work in my garage all the time at 50-55 degrees and I am fine. Generally it is about 65 down there.

I am assuming that, once the foam insulation and batt insulation was up, that I could go ahead and use up my oak wood flooring as a wainscotting up to about the workbench height. It is 3/4' thick and I doubt would warp at all.
 
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Old 12-10-19, 02:23 PM
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You generally want to add drywall (with taped seams) over the studs as an air barrier. Your oak could go on the walls after that with no fear of air leakage between the joints. Yes, the floor is likely the least of your worries.
 
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Old 12-13-19, 03:30 PM
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Not to belabor the point but I will be measuring for stuff this weekend and I want to make sure I get it right.

Do I need 2" foam or would 1" work? 2" is going for $29 per sheet! I live in VA and not the cold climates of New England. So... 1" or 2"?

Do I need to frame the wall out an inch or two from the foam to give an airspace? Some reading I have been doing suggests that.

The insulation... Should it be plain fiberglass with no backing at all? As opposed to the paper backed stuff that staples into place.

The ceiling is the corrugated steel that holds a layer of concrete above that. When I put the foam up and tape the seams and seal the bottom... Should I use expanding foam to fill in the voids of the corrugations before I put the 2x4 framing in?

The drywall... Should it be mildew resistant or something like greenboard for use in bathrooms? I am assuming that after taping the seams I just need to do one coat of finish on the seams... Since it will be covered up.

Thanks for your help!
 
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Old 12-13-19, 05:07 PM
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2" is best, the whole idea is that you need it to be thick enough that the inside surface of the foam is always warm enough to be above the dewpoint. That means 2" in most climates because the ground itself is cold and draws heat away from the home.

You don't want a huge uninsulated air space between the foam and the wall. It only needs to be big enough so that you can make your wall framing plumb. If your foundation is plumb, I would just frame it up with moderate contact. If your foundation is 1/2" out of plumb I would space it 1/2".

Plain unfaced insulation.

I would foam the ceiling first. Spray foam any gaps at the perimeter. Then foam the walls. Then frame the walls, double top plate. Then add ceiling strapping.

Green board should be discontinued, its an obsolete 1960s product. You want mold resistant, for basements.

Yes you just need to bed tape on it at a minimum as an air barrier.
 
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Old 12-14-19, 05:53 AM
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You may curse the cost of foam now but I think in years to come you will be happy you spent the extra money and did it right. Doubling the insulation from 1" to 2" could make a huge difference in the comfort of the room especially if you don't have perfect heating supply.
 
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Old 12-14-19, 10:09 AM
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One last question before I do my measuring and buy the 2" foam.

I have only two concrete walls that face the outside. The other 2 are interior and not exposed to the outside in any way. I assume that there is no need to cover those with foam board. Is this correct?
 
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Old 12-14-19, 10:11 AM
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Correct, assuming interior walls are heated the only reason you might insulate them is for sound deadening.
 
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Old 12-14-19, 11:19 AM
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You mentioned that this is a safe room. Will this only be a gun vault or will it also serve as a "safe room" to seek shelter. Sheetrock barely stops a BB gun so if you want protection against intruders, wind blown debris or keep thieves out you will need to reinforce the interior walls.
 
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Old 12-26-19, 07:20 AM
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To answer the question above... The most economical way for me to have built this in with my house when I designed it was to utilize the space under my huge front porch. It is roughly 30' X 12'. All walls are 10" thick steel reinforced concrete. The ceiling is 6" steel reinforced concrete. I have a 1/2" thick steel in-swing vault door that allows me access via 2 panels to either; open the door if someone tries to lock me in. Or; pull a pin so that I can go inside and it doesn't matter if someone has the combination... They still can't get in. I figured in-swing was the best. If there was a tornado or other natural disaster... The whole house can collapse around the vault and I cannot be blocked in as the door swings open to the inside. The door was the first thing I bought for my house when I built it 5 years ago.

So... New question for the pros..... I have started cutting the 2" foam to size and using Liquid Nail (which says it works with foam boards) to run 3 fat vertical bands of adhesive down both sides and the middle. From what I have read... If there is moisture, this allows it to drain instead of pooling on an adhesive band. So I cut my first 3 panels to size... Test fit them and they were perfect. I adhered each and held in place for a few minutes. I then got various lengths of wood to act as props to keep the panels firmly pushed against the wall. That was Christmas Eve. On Christmas morning... I did another three using the same method, just moving down the wall. I went to go celebrate for most of the day and then came back to tape and foam up the seams that cannot be taped. (Top and bottom basically.) I had done a little foaming before I left as I wanted to see how much it would expand. When I started to tape on the original 3 foam boards... I noticed they were no longer stuck to the wall and were floating free... Out about 1/2" to 3/4" from the wall. They are foamed in place so they cannot fall but I can push the foam back against the wall.

My question is... Is this okay? From what I have read... Since it is sealed it is now its own little environment. If it were to leak at all...Mold growth would be stuck back there with nowhere to go. When I frame... There is no way the foam could ever come down. However... That space would still be there. Does the larger space give mold more of a foothold?

Do I need to use maybe a ramset fastener (If they make such a critter for this) to keep it as tight as possible against the concrete? Or am I okay leaving it as it is?
 
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Old 12-26-19, 03:47 PM
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Not sure what exact adhesive you have. If gluing, I would only use pl300... in 2" round circles (heavy bead circles, not dots or blobs) every 12" on center, not in lines. The circles act as better suction cups. You could do it without glue if you wanted to tapcon the foam to the wall using fender washers or similar along with your 2 3/4" tapcons. It's not like you would need a lot of fasteners if your framing will be tight to the foam.

but yeah I would want them tight to the wall. If the foundation wall is plumb but your foam isn't tight to the wall, well now your foam isn't plumb and you need to have more space between the framing and the foam if you want your wall to be plumb.
 
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Old 01-19-20, 03:18 PM
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Gentlemen,

Thanks for the help thus far. I have finished installing the 2" foam per your recommendations and have also finished studding out the walls. Before I run electrical, insulate and put up sheetrock... I need to decide how I will affix the ceiling. Right now the ceiling is corrugated steel that supports 5" of concrete and another 1" of stone on top of that. The steel stays around 60 - 65 degrees year round and I was thinking about running 2X2s across the top and gluing it to the steel with liquid nail. The 2x2s would also be screwed into the walls on either side. The ceiling is already low enough and I don't want to drop it any lower than I absolutely have to.

My question is if I am safe gluing 2x2s to the steel. My thought is that the glue, when cured, would provide addition protection against sagging... Or wanting to. My widest stretch of ceiling is only about 6' as the room is about 20' long.

Thoughts?
 
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Old 01-21-20, 11:55 AM
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This is the type of ceiling I am speaking of. The height is barely 8' I figure it would probably be better to leave an airspace above the ceiling but I really don't want to lose any more headroom. My thoughts when I framed the wall was that I could run a 2x2 across, on top of the 2x4 and use liquid nail to adhere the 2x2 to the steel corrugation also. Then I could glue and screw the drywall to the 2x2s.

Any words of wisdom? I'd like to get started on this ASAP.


 
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Old 01-21-20, 07:21 PM
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I would foam the ceiling first.
Like I mentioned in post #2 and #6, the ceiling needs insulation just like the walls do. In fact it's even more important to do the ceiling than it is the walls, since the walls are partly below frost, they are warmer in the winter than the ceiling is. The steel will be cold, just like it is outside, and that could frost and possibly drip.

So IMO, you really should have put foam on the ceiling first, then the foam on the walls, (hold up the ceiling perimeter) and then air seal the corner joints... (if the foam on the walls isn't sealed to the foam on the ceiling, all that warm moist air will go right up into the ribs of the steel) and tape all foam seams on the ceiling, before you framed any walls up. Warm moist air rises, so it's possible that will be a problem if you dont do it.

As for what to use on the ceiling, you could maybe mark the low points on the ceiling ribs on the sides of your top plate and after you put the foam up, (use 1 1/2" foam since that's all the space you have for it) put 1x4 strapping 16" on center over the foam... perpendicular to the steel ribs... drill and tapcon the 1x4s to the concrete above through the ribs, roughly every 24" on center.
 
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Old 01-22-20, 06:16 AM
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Yup... Not sure how I missed your suggestion.... TWICE! I guess I was gung-ho to get started on the walls. I will need to rethink how I want to do this now. I really don't want to drill into the steel and concrete above as it is a sealed unit and I don't want any holes in it. The widest span is 6 feet with most being around 5 feet. I think I have enough room to frame the ceiling, slide foam in and still have room on the ends for foam sealer. 2x4s or maybe even 2x3s should work for that.

Thanks for your help!
 
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