Bunker/Panic Room with radiant ceiling

[forAK]

Hello GJ people! After a ton of searching here and the web, I just can't seem to find an answer. Maybe it's just too broad of a question and I don't know what words to use in the search. I'm in the infancy stage of planning a 40x40 extention on my existing garage (32x28) and am wanting to put a bunker/panic room under it. I know I'll need to have an engineer assist in the number calculations but was wondering if any of you might have an opinion if it'll work.

The 40x40 will have radiant heat (in slab). That means the bunker/panic room will have a "hot" roof. I've never seen it before. If doable, it would be pretty cool. The room under the garage would be roughly 10x16 with a large vehicle, most likely a suburban parked over it.

Thoughts? Thanks!

 

[matt_i]

I envy your budget. I think you will end up with post-tensioned concrete to support the loads of a vehicle, cantilevered over an unsupported box/pit area. I think if you commit to a even steady temp it would be OK. I think if you turn it on and off a lot it could lead to trouble from having to manage thermal growth also.

 

[Bondo]

Ayuh,.... Heat rises,.... Don't expect it to be very warm in yer bunker,....

 

[Cyberbear]

You may wish to stub out provisions for adding an air circulating system or fan if you find it's needed after actual usage. Yes, heat rises and concrete is a huge heat sink, so some insulation may be in your future. It would be a shame to spend money for heating you never feel.

 

[Nowater]

What is the expected water table in your area? Are basements common and dry? I suggest you pay close attention to water and drainage issues.

 

[saceone]

I don't know about you guys but if the apocalypse does happen, I'll be outside running over zombies

 

[Kaizen]

for the money you'd spend I'd try to put it next to the garage if you can....even a little away from it if you have the land. probably also use something besides concrete so you can get way more area for your money. its a consistent temp down there so don't think you need too much heat in one of those. do need ventilation and dehumidifier. again this all depends on what level of bunker you want to do.

 

[dfiler2]

Hot air rises, radiant heat goes out evenly in all directions, radiant heated ceilings are fairly common.

http://www.marleymep.com/en/berko/pd-cp-radiant-ceiling-panels/

 

[buddyboy]

yeah warm air rises, the heat in that slab should be the same on the top as the bottom, unless the tubes are closer to one side than the other, and even then it should even out.

the difference would be the air in the garage would heat up at the floor and flow up, and the air in the safe room would heat up at the ceiling and kinda stay there... once the air becomes warm the heat will want to flow to cold... it'll just take longer in the safe room because of lack of the 'heat rises' effect

 

[MarkG]

As has been mentioned, heat rises, so I'd be surprised if there's much noticeable heat at ALL from a heated ceiling, even if it was fairly hot (which it won't be). Hence the reason registers are on or close to the floor.

Even if you did get that slab hot, it would create a very distinct and uncomfortable effect of having the top half of the room too hot and the bottom half too cold!

 

[buddyboy]

Even if you did get that slab hot, it would create a very distinct and uncomfortable effect of having the top half of the room too hot and the bottom half too cold!

i'll have to disagree. radiant heat doesn't work like that, otherwise you would never feel the heat from the sun. just like you feel the heat coming off a parking lot in the summer time, the source is from above but somehow you feel the heat coming from below you?

the same with radiant heat, the heat will radiate from the ceiling and heat all objects in the room. including the floor

if you put radiant heat on the ceiling, the air particles are already warm. where as if you put radiant heat on the floor those air particles are cool and heavy and will be heated and will rise. so yes you'll get more air convection from a floor system, but in the end a person would not be able to tell if the room is heated by a floor or a ceiling system unless they actually touched both the floor and the ceiling to compare

 

[forAK]

I envy your budget. I think you will end up with post-tensioned concrete to support the loads of a vehicle, cantilevered over an unsupported box/pit area. I think if you commit to a even steady temp it would be OK. I think if you turn it on and off a lot it could lead to trouble from having to manage thermal growth also.

I kinda figured that temp would stay steady in the slab to avoid growth/movement. When doing the post tensioning, I wonder if it would get in the way of the pex??

for the money you'd spend I'd try to put it next to the garage if you can....even a little away from it if you have the land. probably also use something besides concrete so you can get way more area for your money. its a consistent temp down there so don't think you need too much heat in one of those. do need ventilation and dehumidifier. again this all depends on what level of bunker you want to do.

I thought about that too. This would be an option but on either side of the garage is rv storage. I figured the suburban is lighter than the motorhomes...

Hot air rises, radiant heat goes out evenly in all directions, radiant heated ceilings are fairly common.

http://www.marleymep.com/en/berko/pd...eiling-panels/

Now this looks like the ticket......going to have to check into this...
Thanks gents for the input!

 

[Jess]

Over head radiant has been used for years. If you are doing hot water radiant in your shop floor, I would hedge my bets and add a loop in the bunker floor, just in case. The pipe is cheap and if you ever decide you need it, it's there. Electric radiant mats were used in homes here for some years, placed above the drywall under the insulation. That ended when it was discovered they were becoming a fire hazard from drying out. It turned out that the idea is used in Europe in plastered ceilings were the mats were imbedded. Thermal mass of concrete will take some time to heat up, but once its going will be very comfortable above and below.

 

[SteveCh]

Heat doesn't rise.

In the case of the panic room, it may not really matter how well you can heat it. How long do you anticipate staying in it??? It will be insulated from outdoor temperature swings, by the ground surrounding it. I see you are in Alaska, maybe the ground temp. is low all the time, and you will be happier down there with some sort of warmth. I guess it depends on what kind of panic scenario would drive you to be down there, and how long.

That being said, two friends of mine [two families], have also built a bunker/panic room. In both cases, they don't anticipate being in it for too very long and simply stashed some good blankets and etc. in there.

 

[mark11]

You had me at bunker.

 

[LS6 Tommy]

i'll have to disagree. radiant heat doesn't work like that, otherwise you would never feel the heat from the sun. just like you feel the heat coming off a parking lot in the summer time, the source is from above but somehow you feel the heat coming from below you?

the same with radiant heat, the heat will radiate from the ceiling and heat all objects in the room. including the floor

if you put radiant heat on the ceiling, the air particles are already warm. where as if you put radiant heat on the floor those air particles are cool and heavy and will be heated and will rise. so yes you'll get more air convection from a floor system, but in the end a person would not be able to tell if the room is heated by a floor or a ceiling system unless they actually touched both the floor and the ceiling to compare

Buddyboy has it right. Heat energy does not rise. Warm air (or any other medium used for heat transfer) is less dense than cool air, so the cool air settles. That's where that line of thought comes from. If you're worried about moving the warm air around due to the lack of convection, toss a decent ceiling fan up.

Tommy

 

[Milton Shaw]

If you are in a earthquake zone I would rethink underground. Could be a deathtrap in a really good shake. What kind of a panic would you be looking for. In Arkansas panic rooms are for tornado's, in Alaska could be bears but you could be stuck down there depending on what the bear can smell.

 

[HoosierMark]

If you build this type of room , make sure the door swings in. You do not want to have the door blocked by debris, for example, from a tornado. If the door swings out, it would be easy to block it. Also make sure you have a way to ventilate the room. Bank vaults have a way to exchange the air in case someone gets locked into it. Panic rooms are nice but they take a lot of planning and specialized systems if they are to function properly.

 

[Richard Cranium]

So what kind of system will you be building into your safe room?

 

[nadogail]

I own a condo, built in '79 - '80, with electric radiant heat in the ceilings; so I know the radiant overhead heating can work.

As I recall, Peters Creek is near Anchorage; so winter temperatures are not generally extreme. But the area is seismically active, well not like California, but still on the Pacific Ring of Fire.

A backup source of heat, or alternate heating system, for WTSHTF during winter, would be something I would want to consider.

 

[sr71]

From experience it will work but you'll need to insulate. My house is all heated via radiant in slab. The finished basement gets heated from the same slab...even with a drywall ceiling. It is amazing how close the temperature is maintained in the basement.

The only problem with radiant comes when/if you consider the cost to install A/C.

 

[tdkkart]

Pretty funny how much bad information shows up in these threads.

 

[theoldwizard1]

I'm no expert, but do you really want your safe room under ground ? You are going to be fighting ground water and possibly flood water.

 

[cat06]

did a house for a guy with a basement under his garage, the basement and garage above was 30 X 50, used hollow core precast for the ceiling/ garage floor with 6" of concrete poured on top of the hollow core, that had rebar every 16 inches and 6x6 mesh and radiant heat tubing attached to the mesh and rebar. Basement walls were poured concrete, he had a two post and a four post lift also.
It can be done

example of hollow core

http://www.oldcastleprecast.com/plants/building-systems/products/HollowCorePlank/Pages/default.aspx

 

[wssix99]

wanting to put a bunker/panic room under it

So, is this something like a tornado shelter or a real "bunker" that you will live in for days on end?

If its the former, then I'd think sinking a separate pre-cast shelter in to the ground in another area would be way less expensive and would probably give you something that is more durable and more maintanable. IMO - It's crazy to spend a bunch of extra money on a wildly engineered structure that you will likely/hopefully never need. (even then, only for several hours at a time) Plus, the added maintenance of having the post-tensioned slab and under-garage space will be a killer for you.

If the later, then some of the logic above still holds. If you expect to really need the bunker, then I'd consider instead spending the money on a nice swimming pool/jacuzzi combo and a bottle of cyanide pills. (If anything ever happens where we need to be in a bunker for an extended period of time, I don't think that living outside of it afterwards will be very enjoyable.)

 

[Gerald O]

As I recall, Peters Creek is near Anchorage; so winter temperatures are not generally extreme. But the area is seismically active, well not like California, but still on the Pacific Ring of Fire...

Not like California? The largest earthquakes in recorded North America history occurred not far from Anchorage. Google 1964 Alaska earthquake.

I grew up in Alaska. Lived in Anchorage and Peter's Creek. Earthquakes were a routine annoyance. People still build with basements all the time up there. I also lived in California for 20 years, and while there were some fair quakes in that time, (lived just about on top of the '89 Loma Prieta quake), would rate it slightly lower than south coastal Alaska for earthquake severity.