Foundation block sweating

[atvkid4eva]

I Have a 40x30 detached shop that has a cinderblock foundation And a concrete floor. You can see one layer of cinderblock and then the framing begins. I have fully insulated the walls with plans to add plywood once the prices come back down. The garage also has two overhead NG Dayton radiant heaters. They are vent free, which I know is known to cause moisture. When I bring the temperature up to about 55degrees or so, I notice the foundation cinderblock will turn a darker color as if it is holding moisture or sweating. Is this normal or is this due to a humidity issue caused by the heaters not being vented? This is only visible from inside the building, not from the outside. I also have two ceiling fans that run continuously to keep the air moving at all times. I would like to be able to set the thermostat and keep the barn a constant temperature throughout the winter, but I’m concerned that the vent free heaters will cause a moisture issue. Is there anything I can do to prevent the cinder blocks from sweating and to control the moisture in general? Can I add a vent to the building, or is my only option to replace the heaters with a vented version?

 

[Captain Spaulding]

The blocks are cold and your heaters are producing warm, wet air. Perfect recipe for condensation.

 

[PWC Repair]

Did your block not get filled with Vermiculite or other insulation?

 

[atvkid4eva]

Did your block not get filled with Vermiculite or other insulation?

No idea, the building was here when we bought the home earlier this year.

 

[atvkid4eva]

The blocks are cold and your heaters are producing warm, wet air. Perfect recipe for condensation.

So is this hurting anything?

 

[Captain Spaulding]

So is this hurting anything?

The moisture will sneak in behind the insulation and cause mold and even water damage unless it is extremely well sealed.

 

[Showkey]

Concrete or “cinder” block are notoriously porous more so than a poured concrete wall.

But either can benefit from paint the wall with two heavy coats of water proofing paint like DRY-LOC. Several brands, water or oil based, the PSI rating is the hydrostatic pressure it can hold back.

 

[NUTTSGT]

You could something like this on the outside of the block.


https://www.menards.com/main/buildi...542-c-9532.htm?tid=4525767614510492433&ipos=1


The inside, you could cover with some rigid foam and then plywood over that. That would create a thermal break from the cold.