Garage built in hillside sweating

[rickyb01]

Ok after I read these post twice and some three times it looks like the question comes down to vent or not to vent. I'm 100% for sure I will insulate the ceiling and walls. Since I'm doing this and redoing the front of the building so I can put in a insulated garage door I don't see why I should vent. By not venting I'm trying to keep the air inside the same constant temp. Now If I go the vent route I don't see why I would want to insulate. So am I on the right track with my thinking on vent and not insulate or insulate and not vent. Thanks Rick

 

[KennyG]

My take is that even with insulation, you will end up with some air infiltration. Ventilation will bring the inside temperature up to about the outside temperature and minimize the condensation if you insulate. My take is that you need to insulate and ventilate. If you only do one, either way I think you will still have very high humidity.

The closest relevant experience I have is with a bathroom in my basement. When I bought the house, water would be standing on the tile floor from condensation in the summer. I redid the insulation and vapor barrier on the walls. I took up the tile and added dri-core panels to the floor, and then put flooring over that. I then put in a small heat recovery ventilator (about 60 cfm) to pull air out and introduce outside air into the upstairs of the house. There isn't a hint of condensation now and it doesn't even feel humid. You won't be able to insulate the floor, but if you can cover the walls and ceiling (you need very little thickness because the surface heat transfer will be much lower with anything other than metal) and get some air flow (you don't need the heat recovery) you should see a great improvement.

 

[ultrarunner]

Having had similar structures... condensation is a problem when warm outside air is drawn in... unless enough air circulates to equalize... guessing a structure with a side fully open all the time?

The blue board does work as long as carefully installed and with edges and seams sealed.

Think of an old metal ice chest... the insulation was enough to separate the zones.

Some of my neighbors with similar workshops have installed radiant floor heat using solar and backup heat which raises the dew point.

 

[rickyb01]

Man I really appreciate everyone's comments but I'm as confused as heck on what to do. Does anybody think by insulating and putting a garage door on for a better seal and running a dehumidifier would work?

I'm not that big on drilling through the top of shelter through all that concrete. It looks like to vent the building I would have to. Maybe hire someone to do it.

Who would you even consider to drill holes in shelter and set up a vent system.?

The way I'm thinking is insulate and dehumidify first. If that doesn't work then add ventilation minus the dehumidify. If that don't work the hel* with it.

 

[ultrarunner]

I tend to go for one time permanent fixes as opposed to ongoing ones that require monthly expense month after month.

Running a humidifier here would get expensive at 25 cents a kW

 

[Boiler74]

I'm one for doing things in steps. I am on the side of insulate first and see if that fixes it. Introducing new holes into the structure could introduce new problems like leaks. Think of it this way, if you are core drilling through steel and concrete to put in a vent later, will going through a little spray foam insulation be that big of a deal?

 

[rickyb01]

You can core drill through roof for the vent, and put fan on it. You need an inlet for the air to come in core drill another hole opposite it and plumb it down to close to he floor for the air to come in . Tom

When I redo the front wall of storage I can run 4" PVC pipe to do this. On one side I can run the length of the building at the top with four T's and on the other side I can run a duplicate pipe on the bottom. No drilling thru concrete at all. Figure out a way to use an exhaust fan with top pipe and I think it will work.

 

[ohmyback]

Sounds like you almost have the same situation as a damp crawl space. Some of the local outfits advertise spray foam to create a conditioned air space.

 

[ruffdog]

Maybe just live with it for a year first. You already know how "venting" it works by opening the doors up on a warm humid day. Call the previous owner and ask him your questions and see what he says.

 

[GPintheMitten]

When I redo the front wall of storage I can run 4" PVC pipe to do this. On one side I can run the length of the building at the top with four T's and on the other side I can run a duplicate pipe on the bottom. No drilling thru concrete at all. Figure out a way to use an exhaust fan with top pipe and I think it will work.

No expert here, but thinking about the venting and air exchange. If the outside air is warmer than the "cave space" won't it still condense on surfaces that are colder than the air?

 

[ruffdog]

No expert here, but thinking about the venting and air exchange. If the outside air is warmer than the "cave space" won't it still condense on surfaces that are colder than the air?

Yep, just like water is condensing on the concrete floor where air blows under my sheds walk-in door. If I would open the big door, everything would be wet. The OP's boat house was probably super wet because the relators kept opening the doors for open houses.

 

[rickyb01]

Ok you guys I get a plan in my head and then you guys scramble it up again. The current situation on the boat house is it just ain't sealed at all. It has no problem getting air with all the cracks. Now I can see where the air is not escaping and just sitting up on the metal ceiling. I can see a lot of daylight between and around those barn doors. This is why I want to redo the front with a insulated garage door.

Ok some say vent and insulate and some say insulate and not vent. I guess this will be a trial and error situation. I now understand I will insulate the ceiling with spray foam and redo the front with an insulated garage door. After doing this I will see what happens and If this doesn't work I can add a bath exhaust vent along the top and run out the front of wall. I can also run on the opposite side of building a vent that goes along the bottom of the floor and plumbs up and run out the front of the wall. This way I don't drill through any concrete.

Let's also remember that I ain't living in this boat house but I do want to try and make it a dry storage place.

It's going to take a while but I will try and keep you guys up to date on how all of this has worked out. Rick

 

[s219]

When we moved into our new home, within a few weeks I had mold/rust issues in the garage. This is a new home with an insulated garage and insulated doors, and vapor barrier under the concrete floor slab. Very tight and dry. The floor slab in the garage stays very cool in the summer, more so than other garages I have owned, and it was causing issues -- whatever humid air was in the garage would cool and moisture would condense everywhere.

Some people suggested ventilation, but I didn't see the point when the garage was tight and letting in more humid air wouldn't solve the humidity and condensation problem, and certainly wouldn't counteract the cold temperature of the slab. So I installed a dehumidifier, and it solved the problem. I also put a ceiling fan up that constantly runs, to help circulate air. I think the dehumidifier does the heavy lifting, but air movement can't hurt.

Interesting thing is that this is a 3-bay garage, with one bay separated off by a wall/door and used as a workshop. I was thinking I might need a dehumidifier in both sections, but as long as I leave the passage door open, the workshop stays dry. The dehumidifier really does a good job pulling moisture out of the air in the entire space.

I think the basic question is this: what is the typical humidity of your outside air, and will introducing it into the garage help dry it out, or make no difference, or make it worse? Around here, we routinely hit 90% or higher humidity all summer, and so it became obvious to me that venting and pulling in outside air was not the answer. In a drier climate, it would be.

 

[ultrarunner]

What kind of upfront cost and ongoing cost is associated with your humidifier?

I would imagine it is seasonal?

Had the same constraints when I built this cabin...

Typical construction is all concrete block which works as long as home is heated/lived in.

My problem is the home is shuttered 11 months of the year... my only choice was to go timber the upstairs living area... no mold or moisture issues because the wood is never cold enough for the moist air to condensate.

Keeping the surfaces about the dew point is the key...

I would think blueboard or spray on would help immensely.

That said, I'm also a believer in living all 4 seasons before committing to big expenses.

 

[rickyb01]

When we moved into our new home, within a few weeks I had mold/rust issues in the garage. This is a new home with an insulated garage and insulated doors, and vapor barrier under the concrete floor slab. Very tight and dry. The floor slab in the garage stays very cool in the summer, more so than other garages I have owned, and it was causing issues -- whatever humid air was in the garage would cool and moisture would condense everywhere.

Some people suggested ventilation, but I didn't see the point when the garage was tight and letting in more humid air wouldn't solve the humidity and condensation problem, and certainly wouldn't counteract the cold temperature of the slab. So I installed a dehumidifier, and it solved the problem. I also put a ceiling fan up that constantly runs, to help circulate air. I think the humidifier does the heavy lifting, but air movement can't hurt.

Interesting thing is that this is a 3-bay garage, with one bay separated off by a wall/door and used as a workshop. I was thinking I might need a dehumidifier in both sections, but as long as I leave the passage door open, the workshop stays dry. The dehumidifier really does a good job pulling moisture out of the air in the entire space.

I think the basic question is this: what is the typical humidity of your outside air, and will introducing it into the garage help dry it out, or make no difference, or make it worse? Around here, we routinely hit 90% or higher humidity all summer, and so it became obvious to me that venting and pulling in outside air was not the answer. In a drier climate, it would be.

I'm here in central Arkansas and I can assure you we have high humidity but I get your point. Rick

 

[s219]

What kind of upfront cost and ongoing cost is associated with your humidifier?

I would imagine it is seasonal?

That is a sweet little cabin you built! Where is it located?

The dehumidifier (70 pts/day) was about $250-300 but I don't have any idea of the operating cost (never had a baseline electric bill to compare with). I leave it powered on year round. Typically it kicks on once an hour for 5-10 minutes in the most humid times of year. During drier times of the year, it might come on 1-2 times a day or not at all.

Dehumidifier will be 3 years old this summer. I was reluctant to add another appliance into the household, so if a better way ever comes along, I am all ears....

 

[ultrarunner]

That is significant... even for a 3-car garage.

The cabin in a few minutes outside of Salzburg Austria on the road to the Lake District...

I added the back half in 2009 for a property master bedroom suite with bathroom... not typical as everyone has bathrooms off hallways... often even the bath is separate from toilet... what can I say... I did it my way... drew all the plans that were approved by the city plus spent months over several years on the construction...

The last addition is the double garage on the other close side of the property on the right... had a lot of comments about only an American would have a summer home for 4 garages!!!

The other picture is looking is a neighborhood shot... when I built the original cabin... none of the neighbors homes had been built... for 16 years I was all by myself...

My neighbors are all trades people... the first house on the left is owned by a roofer... yes... all copper roofing... even the kids playhouse and stainless steel fence panels...

Moisture and summer humidity is a real concern there with so much block construction... radiant heating is real big and does wonder to control humidity... if the floor is warm a lot of livability issues go away.

 

[s219]

What a cool neighborhood -- looks classic Austrian. I was in Vienna once for a few days many years ago, and really regret that I did not get out to the countryside. Saw a little bit, and it was beautiful. So do you plan to retire out there or will it just be a summer home?

 

[ultrarunner]

Good question and my apologies to the rickyb01 for getting off topic.

Mom had bought the little plot of land over 50 years ago...

Just like here... there were big changes coming to land use and we were advised to build something or the land would soon become open space green belt forever... with wetland enhancement.

So right out of college I spent 6 months on the initial build... over the years have done additions.

It kills me to have nice garages there and be stuffed to the gills here.

The double stand alone garage was also one of the deals with zoning... they were changing the outbuilding rules... so I built the garage.

I would be comfortable there... it is different and a slower pace of life... frustrating as h*ll not being able to run to the Home Depot in the evening or on Sunday... after awhile you get use to it... plan better and more family time...

Dampness is a real concern in forested and meadow areas... there are a lot of building techniques to combat it and then simple things like not opening the basement windows when it is hot and humid outside...

Also damp room white wash for the walls...

A little warmth goes a long way as does mixing up the air with a fan.

I learned a lot there... like having to have a case of beer onsite everyday to cover lunch or after work for the workers... ;-)

I do admire that every neighboring home is owner built even if it takes years and on the buy material as you can afford it plan after the walls and roof are up...

Picture of my 3 California nieces in the "Princess" dresses I bought them and a winter picture...

 

[SPYDERLK]

Looking at buying a home that has a 24x20 garage built into a hillside. It has double barn doors and a 36" walkout door in the front. The floor is concrete, the walls are cement block and the ceiling is about 12" of poured concrete with real heavy gauge steel roofing covering the concrete on the ceiling. The whole garage is in the ground except for the front. When I walked into it today it had water from condensation dripping off the metal roof. Any idea's on getting rid of condensation. I would like to store tractor and four wheelers in this space but don't want to invite rust. Outside of keeping the doors open it has no ventilation so maybe a whirlybird on top would help. Any other idea's. Thanks Ricky

U R in trouble in the warm season. I would run a dehumidifier and limit ventilation to that needed to vent most of its waste heat outside.