Storm Shelter build

AaronM · Jul 18, 2018

This brings back all kinds of memories from when we built our house. The masons built the block walls for the storm room and they turned out fine but the builder's 'handyman' was put in charge of the concrete roof. It was a very hot day and he was out there by himself mixing & pouring the concrete. I just didn't feel like the necessary checks & balances were in place so, after he left I climbed up there to inspect the job. I dug into the fresh concrete and found he had cut all of the rebar off flush with the tops of the walls (not bent over into the roof) and basically just buttered the wooden roof supports with concrete. The concrete on the roof was maybe 1.5" thick. Just thick enough to cover a couple foot long loose pieces of scrap rebar that the laid up there and nothing tying the roof to the walls at all.

It was a complete mess to fix and the two times my family and I retreated to the storm room did not give me a warm fuzzy feeling.

3Ts · Jul 18, 2018

First of all, the door is really nice. The company that builds them does a nice job and is easy to work with - and specifies what the dimensions are for the opening, etc. If the manufacturers directions had been followed, it would have been much better.

As for a footer? It's on a 4" slab many 10's of feet wide, what more could you want? (tongue-in-cheek). No, it was built on top of the slab. There are cross beams in the slab 16" thick, but I don't know if one is under the concrete block - I just hope so.

My recommendation after all this is to use 3/4" plywood to form for a poured concrete wall (with the door already in place) and leave the plywood in place as an anchor for the drywall or other finish for the room.

3Ts · Jul 18, 2018

I do have pictures of the foundation of the house before concrete was poured. I'll have to see if I can get them posted after a bit.

As for insulation, the house is a spray foam house and the sub said they have a nozzle that they can spray foam between the block and the studs. I assume they did that, but don't know. That is an operation I stay away from while they are spraying.

As for venting, it's not as good as it should be. What is in-place is a regular HVAC duct to provide heated/cooled air. There is also another HVAC duct (also in the ceiling, but should be near the floor) that sucks air from the closet and feeds it back into the intake of the air handler. I did make them prove that there was an actual air flow, it's not much but does hold a tissue up. There is also a 3/4" gap at the bottom of the door across the full 3' width which provides 27 sq. in. of ventilation as well.

This is the first storm room the builder has done and pretty much turned it over to the foreman (whose primary language is not english) to build.

ovrszd · Jul 18, 2018

Following

3Ts · Jul 19, 2018

In an earlier post I implied that there was no foundation for the block walls, I was wrong. Here's the foundation just before the concrete is poured. The square closest to the camera is pretty much where the storm room is. The slab has 12" wide x 24" deep footers around the outside and 12" x 16" internal beams. The blue is the reinforcing cables and are about 3' apart which varies depending on location. I've heard of Post-Tensioned concrete used in commercial buildings before, but this is the first time I've seen it in residential use. I really like it. The concrete does have cracks in the slab which started showing up a week or two after the pour. (The concrete here is not that good and DOT will not use it for anything and the one company is the only one within an hour's drive.) The foundation company lets the slab cure for several weeks then comes out and tightens the cables which closes the cracks and keep the whole slab under compression.

The foundations the builder does is one of the best in the area. I know this post on the storm room does not sound very good on the storm room, but that is only one part of the house. He learns from his mistakes and he's said he'd do the next one differently. Unfortunately, he learned at my expense on this one, but I benefited from his experience in other areas.

EddieWalker · Jul 19, 2018

Very nice. A huge pet peave of mine, and a red flag on everything else that's done, is not seeing chairs under the rebar. Nice to see they used them on your foundation. Seeing that you have red clay, I'm surprised that they went with beams under your slab. I know that's done in the DFW area where it's all black clay because of the amount of movement you get in the soil, but red clay is so stable that it's never an issue up here in the Tyler area.

On the FEMA plans that I'm familiar with, and I didn't open your link to see if it's the same plan, they want the rebar bent and tied into the footings in the slab. Then you lower the cinder blocks over the standing rebar. I did my swimming pool this way and it's a HUGE pain, but worth the effort for the amount of strength it provides.

Cracks after a pour are from too much water. Adding water makes it easier to spread, but then that volume that the water creates is lost to evaporation and curing, leaving a void in the slab. Cracks are created by that void.

3Ts · Jul 19, 2018

They were supposed to put the rebar in and told me that was the plan, but then didn't do it. They ended up drilling holes and epoxying the rebar into the slab.

EddieWalker · Jul 19, 2018

From the way the FEMA Plans are drawn, the want it to withstand a nuclear bomb. I'm sure yours will be plenty strong enough for anything that comes your way.

3Ts · Jul 19, 2018

Ok, here's the finished product photos.

Here's the inside looking out. That HVAC vent in the ceiling is a return air vent (air moves from the closet to the intake of the air handler) and the supply vent is above where I'm standing. You can see some of the wood graining on the ceiling. That ceiling is simply painted concrete. They used Hardie sheets to make the wood grain in the concrete.

and the door will open almost against the wall (165* according to mfgr). Mine won't go quite that far because of the drywall in the way of one bolt (which I may adjust later).

Deere Dude · Jul 19, 2018

3Ts said:
Ok, here's the finished product photos.

View attachment 563453

Here's the inside looking out. That HVAC vent in the ceiling is a return air vent (air moves from the closet to the intake of the air handler) and the supply vent is above where I'm standing. You can see some of the wood graining on the ceiling. That ceiling is simply painted concrete. They used Hardie sheets to make the wood grain in the concrete.

View attachment 563455

and the door will open almost against the wall (165* according to mfgr). Mine won't go quite that far because of the drywall in the way of one bolt (which I may adjust later).

View attachment 563456