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View Full Version : reinforcing floor for weight of safe



swampstalker
01-13-2013, 07:21 AM
I thought I've seen a post on here about this but couldn't find anything. I am getting my new safe in a few weeks and was wondering if anyone has supported there floor due to the weight of the safe. The safe is 42in x 27.5 in so that works out to 1155 square inches and the safe weighs 1125lbs, so a little under one pound per square inch. Now I figure that with all the stuff Im gonna put in it it will add about 700lbs. So thats 1.6lbs per square in. This also works out to about 228lbs per square foot. Is this weight to be conserned about. The safe will be on an outside wall and an interior wall, the interior wall is right above the main support beam in the basement. Thanks for any input.

jmanz6
01-13-2013, 08:33 AM
228lb/sq ft isn't very much. I weigh that much and the floors don't hve to be reinforced for me to walk around my house. If you are putting it near the main support beam of the house, you should be fine. It will spread across 2 floor joists so it will not be loading over open floor space. That is still a big safe. What kind did you get?

swampstalker
01-13-2013, 11:30 AM
Got the Liberty Lincoln 50

teecro
01-13-2013, 11:41 AM
228lb/sq ft isn't very much. I weigh that much and the floors don't hve to be reinforced for me to walk around my house. If you are putting it near the main support beam of the house, you should be fine. It will spread across 2 floor joists so it will not be loading over open floor space. That is still a big safe. What kind did you get?

One of the absolute worst at floor loading is your refrigerator as it puts several hundred pounds of load on 4 small pads/wheels at the corners.

If a person was/is really worried about floor loading one of the best ways would be a slightly over-sized "PAD" for the object to set on top of; this pad can be nothing more than a piece of 1" thick plywood...

After that if you can easily get under the floor it is fairly easy to add 2ndary lengths of plywood to the underside of the floor itself and follow that up with supporting lengths of 2 by material to the floor joist. Be sure to use construction adhesive and suck your timber up tight with strong screws etc. I've done this with some noisy old stairs and when done they stay silent for many years to come.

jjkukla
01-13-2013, 09:04 PM
I'm sorry, but 228 lbs per square foot IS a lot. Michigan Residential Building Code only requires a uniformly distributed design load of 40 lbs per sqft (if I remember correctly) for most rooms in a house. Now, this means 40 psf distributed over the ENTIRE room... so it is possible that you might be able to support your safe how and where you want to depending on what else you have in that area.
If you want to be absolutely sure, contact a structural engineering firm and have them examine your framing. It'll cost you about $500... but if it goes crashing through your floor, good luck getting insurance to cover it.
FWIW, I am a licensed professional (structural) engineer here in Michigan and I used to perform forensic investigations for a local firm. You'd be surprised at some of the things that people try to claim on their insurance!!
Good luck with your installation.

10x25mm
01-14-2013, 06:07 AM
The first step is to go down into your basement and carefully inspect the condition of the structure under the safe location. Any splits or cracks in the joists? Do the joists sit tight on the basement wall top plates? Have the joists been damaged by holes for electrical wiring, attachments, etc.? Can you determine the condition of the basement walls? Any issues here must be addressed before installing the safe.

As long as this inspection finds no uncorrectable problems, you probably will be OK as long as the safe is set next to a wall so the weight is directed through the joists into the basement wall (a wall where the joists are perpendicular, which is the best situation for strength). The structural standards for flooring in residences are based on loads in the middle of the joist's span. The good news about safes and refrigerators is that they are placed up against a wall where they direct the vast majority of their load into the basement walls, not the center of the joist span.

Your safe is 42 inches wide, so you want to spot it over three joists, not two. [Again, I am assuming that the safe location up against a wall where the joists are perpendicular, the best situation for strength. Joists parallel to the wall is a much less satisfactory situation and can pose long term problems.] You may have to drill a small (1/16") hole through the floor from the basement to precisely locate the joists from above at the safe location. Cut three 27.5 inch long pieces of 2x6 wood (good quality stuff, not framing grade garbage) and wipe them down with linseed oil to stabilize them against humidity changes. Position them over your joists and use a dab of adhesive at their centers to hold them in place so they don't get knocked out of location during safe spotting. You will have to remove carpeting underneath these 'feet', but other types of flooring can be left under them.

It is critical that the safe's load be uniformly distributed on these feet. After the safe is spotted, you will need to shim between the safe and its feet to get even bearing. Do this with four toe jacks and thin (1/16 inch thick) galvanized steel plates. You can use a long level before the safe is spotted to 'preshim' the feet to minimize the post spotting shimming.

If you want assurance that your safe installation is OK, get a laser distance measurer and measure the vertical distance between the basement floor and the bottom of each joist at three different locations on each joist (a total of 9 readings), front, middle and back. Do this before and after the safe installation. Mark the measurement locations (floor and joist) with a marker so you can get exactly repeatable measurements. As long as your joists do not sink more than 1/4 inch, you are good to go. You will need to repeat these measurements after the safe is loaded. Any measurement which indicates that a joist has sunk more than 3/8 inch is of great concern.

If you get to the 3/8 inch redline, there are several things you can do. The simplest is to install one or more floor jacks under the safe. The best remedial measure is to 'laminate' a 1/16 inch thick piece of steel to each joist under the safe. This is the most common method of repairing defective joists in old houses.

Signess
01-14-2013, 09:07 AM
First things first.... what size joists are we talking here? 2x10, 8, 6????? Anything less than 2x10, you're going to need to double them up, or build a wall under it in the basement.

Ok.... let's simplify things here a little shall we. I'm a carpenter, been doing this crap for 25+ years. Unfortunately! :togo:

This appies to 2x10's...

First off, I'll put my .02 in on how I feel your situation is at the moment. For temporary situations. Your safe, and framing will be fine. However, over time.... your joists will tend to "droop" with the weight of the safe. And in saying this, I'm assuming you have no future plans of moving this big beast again???

Next, is your basement finished or framed to be finished? And is it possible to build a wall or closet of some sorts in the basement under the area for the safe? All of your worries will be for nawt if you can build a small wall under the safe.

Can you double up the 3 joists the safe will be bearing on? A little more difficult than building a small weight bearing wall, but not all that bad if no heat or cold air runs in that area. Duct work is a simple fix though. The doubled joists only need to bear on the walls 1 1/2 inches, and you CAN if need be, shave the joist in order to allow it to twist into place. Shim after if need be. Then nail the piss out of them! 2x10/8, 3 nails every 16-24 inches.

Another alternative, although not as structurally sound is... Solid blocking, or bridging the joists across the length of the room the safe is going in. What I mean by that is putting blocking in perpendicular between each joist across the entire length of the room. Assuming the wall on the first floor is directly above the beam in the basement for bearing purposes... measure off the beam, equal distance to what the safe is. And start the blocking there.

Solid Blocking
http://www.infoarena.com/pics/joist/finish/sisters_finished.jpg

I don't know what your situation is, finished basement, or what.... but this is an alternative also. Although cumbersome... (Borrowed photo from the web I didn't place the red arrow)

http://www.infoarena.com/pics/joist/sag.jpg

swampstalker
01-14-2013, 09:30 PM
I have 2x10 joist and there will be three of them under the safe. They appear to be in good shape no crack or rotting but they do have a 1/2in hole for a wire. The basement is not finished and I think that ill double up the floor joist and also block them. When i double up the joist do i run the board from the outside wall all the way to the beam running through the center of the basement? and if i block it i would measure 27 in off of the main beam because thats how deep my safe is and the main beam is directly under the interior wall , is this correct? Thanks.

Signess
01-15-2013, 06:22 AM
I have 2x10 joist and there will be three of them under the safe. They appear to be in good shape no crack or rotting but they do have a 1/2in hole for a wire. The basement is not finished and I think that ill double up the floor joist and also block them. When i double up the joist do i run the board from the outside wall all the way to the beam running through the center of the basement? and if i block it i would measure 27 in off of the main beam because thats how deep my safe is and the main beam is directly under the interior wall , is this correct? Thanks.

Yes, cut the joist size to bear 1 1/2 inches on each wall (exterior wolm. sill plate & beams wolm sill). This will allow you to sneak the joists into the 14 1/2 inch cavity between joists. Anything longer, and it probably won't be possible unless your joists cantilever (hang past) the foundation/basement wall.

If you are doubling the joists, you really won't need to add the blocking. Unless you have to knock out some bridging ( 1x4's installed in "X" crossing style between joists). But, as they say... an ounce of prevention. It certainly WON'T hurt. Anyways if that's the case, place the blocking in the areas you had to remove the bridging, and call it good. Now... if there is no bridging to replace. And you just want to add the blocking for "piece of mind". You can just measure approx. 3 feet off beam, and place the blocks there. That number isn't that important now that we've doubled the joists. It just helps to distribute the weight across the joists, and avoids future twisting.

I'm better at building than I am at explaining. So, if there is anything that you are vague on, or I was lacking in my explanation. Feel free to ask! :wink: Regardless of how silly it may seem. Nothing is too silly in order to save yourself some work in the long run. Good luck, and I hope this solves your concerns. :cheers:

swampstalker
01-15-2013, 07:32 PM
yes this does help, thank you for explaining it and for providing the pics. now all there is to do is add one more thing to the list of home projects.

1eatbUnn1es
01-15-2013, 08:59 PM
This might not be much help, as all homes are different. But I have a fish tank that puts about 333lbs/sq foot in my living room, interior wall. It is over a support beam with two concrete pillars underneath.

skidooboy
01-16-2013, 03:13 PM
put it in the basement, problem solved. ski

kjs357
01-16-2013, 03:16 PM
Ditto

Daniels
01-16-2013, 04:13 PM
Think of those old cast iron tubs that weigh 400 pounds empty and then get 400 pounds of water in it. LOL But that wasn't a constant load for extended periods.

If you are really concerned about it and have a basement or crawl you could also put in a stanchion under that area. That might end up being in a goofy place in the basement though.

10x25mm
01-17-2013, 12:39 PM
Yes, cut the joist size to bear 1 1/2 inches on each wall (exterior wolm. sill plate & beams wolm sill). This will allow you to sneak the joists into the 14 1/2 inch cavity between joists. Anything longer, and it probably won't be possible unless your joists cantilever (hang past) the foundation/basement wall.

This is why the restorers of old homes repair damaged joists with 1/16 inch steel sheets laminated to the existing joist. It is easy to get a full length piece of steel in (you can get it to shorten by 'rippling') and glue/screw it into place. It provides better strength and stiffness than 'sistering' with wood, although sistering with wood also works.

soupyu
02-04-2013, 01:35 PM
Good to learn:grin:

Detroit Holster
06-04-2013, 09:43 AM
Thanks for the info - very helpful.


The first step is to go down into your basement and carefully inspect the condition of the structure under the safe location. Any splits or cracks in the joists? Do the joists sit tight on the basement wall top plates? Have the joists been damaged by holes for electrical wiring, attachments, etc.? Can you determine the condition of the basement walls? Any issues here must be addressed before installing the safe.

As long as this inspection finds no uncorrectable problems, you probably will be OK as long as the safe is set next to a wall so the weight is directed through the joists into the basement wall (a wall where the joists are perpendicular, which is the best situation for strength). The structural standards for flooring in residences are based on loads in the middle of the joist's span. The good news about safes and refrigerators is that they are placed up against a wall where they direct the vast majority of their load into the basement walls, not the center of the joist span.

Your safe is 42 inches wide, so you want to spot it over three joists, not two. [Again, I am assuming that the safe location up against a wall where the joists are perpendicular, the best situation for strength. Joists parallel to the wall is a much less satisfactory situation and can pose long term problems.] You may have to drill a small (1/16") hole through the floor from the basement to precisely locate the joists from above at the safe location. Cut three 27.5 inch long pieces of 2x6 wood (good quality stuff, not framing grade garbage) and wipe them down with linseed oil to stabilize them against humidity changes. Position them over your joists and use a dab of adhesive at their centers to hold them in place so they don't get knocked out of location during safe spotting. You will have to remove carpeting underneath these 'feet', but other types of flooring can be left under them.

It is critical that the safe's load be uniformly distributed on these feet. After the safe is spotted, you will need to shim between the safe and its feet to get even bearing. Do this with four toe jacks and thin (1/16 inch thick) galvanized steel plates. You can use a long level before the safe is spotted to 'preshim' the feet to minimize the post spotting shimming.

If you want assurance that your safe installation is OK, get a laser distance measurer and measure the vertical distance between the basement floor and the bottom of each joist at three different locations on each joist (a total of 9 readings), front, middle and back. Do this before and after the safe installation. Mark the measurement locations (floor and joist) with a marker so you can get exactly repeatable measurements. As long as your joists do not sink more than 1/4 inch, you are good to go. You will need to repeat these measurements after the safe is loaded. Any measurement which indicates that a joist has sunk more than 3/8 inch is of great concern.

If you get to the 3/8 inch redline, there are several things you can do. The simplest is to install one or more floor jacks under the safe. The best remedial measure is to 'laminate' a 1/16 inch thick piece of steel to each joist under the safe. This is the most common method of repairing defective joists in old houses.

DP425
06-04-2013, 09:54 AM
After that if you can easily get under the floor it is fairly easy to add 2ndary lengths of plywood to the underside of the floor itself and follow that up with supporting lengths of 2 by material to the floor joist. Be sure to use construction adhesive and suck your timber up tight with strong screws etc. I've done this with some noisy old stairs and when done they stay silent for many years to come.


This is NOT the proper way to reinforce a floor; the load is carried by the bottom 1/3 and top 1/3 of the flooring members (joists) through compressive and expansive properties of the wood fibers. What is described above will do nothing more than give additional strength to the sub-flooring between joists.

Full-length sistering is your answer. If you're unsure what that means, it's adding a second floor joist of identical dimensions to the sides of your existing joists with construction adhesive, bolts and screws or nails. The bolts assist in good contact bond with the adhesive.


edit: Should have read further down- 10x25mm did a great job in his post. But remember, interior, partition walls can sometimes be in the middle of a span. You really do have to go under and look to see the safe's location relative to the bearing structure.

dab102999
06-04-2013, 11:06 AM
I am not doubting any input that I have seen but my question is..do all of you with safes have reinforced floors??...and if this is a real problem I would think that on the numerous gun sites I am on I would have seen at least one post of a problem. Not saying there isn't one but I just think there is a lot of overthinking going on here.

DP425
06-05-2013, 11:08 AM
I am not doubting any input that I have seen but my question is..do all of you with safes have reinforced floors??...and if this is a real problem I would think that on the numerous gun sites I am on I would have seen at least one post of a problem. Not saying there isn't one but I just think there is a lot of overthinking going on here.



You don't have to have your safe fall through your floor to have a problem. excessive weight loads can cause sagging that is only reversible with adding support structure. There are also a variety of other things this can effect that a lot of people perhaps wouldn't consider- finished room below your over-loaded floor? High likelihood you'll see more problems with your drywall, especially on the ceiling which most would just attribute to shoddy workmanship.

MI-1911
06-16-2014, 06:46 AM
put it in the basement, problem solved. ski

Unless it floods! :boat:

mike657894
02-23-2015, 09:46 AM
thanks for all the good info

MI-1911
02-23-2015, 09:52 AM
put it in the basement, problem solved. ski

Until it floods!

oldmann1967
02-26-2015, 09:47 PM
[QUOTE=jmanz6;1877433]228lb/sq ft isn't very much. I weigh that much and the floors don't hve to be reinforced for me to walk around my house. If you are putting it near the main support beam of the house, you should be fine. It will spread across 2 floor joists so it will not be loading over open floor space. That is still a big safe. What kind did you get?[/QUOTE

I am lost. There are 144 square inches in a square foot.

rdarabos
02-27-2015, 07:49 AM
I am not sure if this helps, but I just bought a safe from able safe co , and I was concerned about weight on the floor. Well I am here to tell you I have a 750# safe with the brackets on each side for lifting , it sits on that and have no issues at all. I was also told " you'r going to need 4 big guys to help you get it there". My son , who weighs 150 and myself at 62 got it in without any problem . You got to be smarter then the job you are doing.

oldmann1967
02-27-2015, 11:36 PM
You lifted 375lbs each? Or do you mean the door was removeable, weight removed from the inside, and carried it in pieces? That would be a human feat of strength!

rdarabos
02-28-2015, 07:24 AM
No oldman1976 , did not pick any thing up just slid it off truck on heavy duty plank on to porch, than slid it in front door rocked up one side put rug under then did other side and slide throu house . No lifting to heavy for that . Front porch is level with front door . Really was not bad at all, probably less then 20 min to put in place

oldmann1967
02-28-2015, 09:35 PM
That is working smarter for sure!