Waterproofing for concrete blocks?

[Suzu]

I live in Tornado Central in a mobile home and it scares me half to death when we have tornados in the area, so I'm thinking of building a shelter. I only have flat land to build on, therefore the structure will only be partly underground, and the remainder bermed with the excavated earth.

My plan is to use concrete blocks with mortar and rebar in the center and Q-bond on both sides, but I am not sure if Q-bond waterproofs the blocks. Has anyone used this stuff before? If you have to use a separate waterproofing agent, do you apply it over or under the Q-bond?

[RB]

It's much safer to place the mobile home somewhere distant from where you live. Then the tornados will touch down distant from your home.

Trailers are tornado magnets.

RB

Suzu wrote:

[Art]

There are pre-made in slab units that might be a better idea. Also suppose you aren't home or are asleep or the tornado forms directly overhead so there is no warning. Seems to me it is something not worth worrying about.

[Suzu]

I assume you are joking. If I live in the mobile home, how do I place it distant from where I live?

[Suzu]

I plan to make it large enough to use as an office, spare bedroom and storage space, so if the weather is unsettled I can just go down there for the night. Also plan to keep valuable items stored there so if I'm not at home, and the mobile is destroyed, I won't lose everything.

Of course in the case of a direct hit it would not matter where I was, would it? But a near miss that would destroy the mobile home would not hurt an underground shelter.

[DanG]

To be safer, I would recommend a cast-in-place concrete shelter. If you want to work with the block, I would rebar every cell and slush solid. I would not depend on the Q-bond to provide the total structural integrity. Q-bond (I'm not sure if it is one of the cementitious or fiberglass products) is meant to take the place of setting the blocks in mortar. It makes it more DIY friendly. I would not depend on it for waterproof. Below grade, you should have gravel drainage to either a sump or day light, waterproofing membrane to keep the water out of the hidey hole. Above grade, paint should provide the water proofness that you require.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Keep the whole world singing. . . . DanG

only be partly

center and

the blocks.

[Tom Baker]

Looked at Q Bond PDF. It appears to be similar to "surface bonding" material I used on Jacksonville FL fire station in the '80s. I had a chance to see it abut 10 years later and it was in good shape. I don't remember using any finish on it. Parging foundations is an old means of dampproofing. If the soil is reasonably well drained and the water table is not near the floor level, I should think you will be o.k. Joints are always a problem with water infiltration, so detail them carefully.

Tom Baker

[Art]

Just thought I would add that we recently dug out our stoop which goes down

13 feet underground and was poured with the basement walls. After installing a drainage pipe, rather than filling it with gravel and dirt I considered making it into a tornado shelter with a door from the basement. The basement itself is a daylight basement with lots of steel beams and would not be a terrific place during a tornado. In any case I dropped the idea and fiilled it with gravel and dirt before replacing the slab over it. Could have been my panic room.