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What will you be doing with the floor? is it concrete or wood?

Spray foam is a vapor barrier. Why not build just the interior studs, have them spray closed cell foam and then skin? Seems to me to be workable. Plus it will be structurally attached to the existing structure. If you use the sheeting it will be a bond breaker and will not add appreciably to the vapor barrier.

Originally Posted by craig1

use a good TXV and set up the system to pump down on shut off and you shouldn't get any slugs of liquid.

Well I'm going with a Beacon II setup (already have one on the medium temp box) so it has the pump down covered. I know some kinda frown on Beacon systems but I've had good luck with them. I just keep a spare control board, sensor packs and a TXV in a box in the store room.

Originally Posted by foxtrot

But with a semi-herm not having any shell to take any accidental slugs of refrigerant is it something to consider vs the rust and other issues down the road?

use a good TXV and set up the system to pump down on shut off and you shouldn't get any slugs of liquid.

Originally Posted by foxtrot

Thanks its just I got a little thin skinned after getting read the riot act by a few guys at the supply houses when I asked them a few questions and that's why I decided to try you guys here on HVAC-TALK.

No problem. I understand how that can happen. However, I know almost all the HVAC/R contractors in Galveston. I worked for one for 26 years on the island. I've worked on a few stick-built walk-in-coolers/freezers. One of the long-time popular restaurants on the island has a couple of stick-built walk-ins in their kitchen. If you were in the business in Galveston, I probably know you. In fact, I'm pretty sure I know you. If you want, I can call my ex-boss or one of the other contractors I know who won't give you a hard time and maybe hook you up with one of them. You probably know them. Let me know and I'll do what I can to help. If not, that's cool, too.

FRP sure does make for a nice finish. Epoxy can get pricey too. I would feel safe with the FRP roller glued down and no fasteners going thru. The seams I would consider putting silicone into the H dividers then inserting the panel. It would be nice if we could get more suggestions.

Well since everything in the cooler is "packaged" in buckets or bags the health dept. told me that I can use plywood as long as its epoxy coated. If I scratched the FRP and just used plywood with the vapor barrier on the outside would it be an issue?

I don't mind putting vapor barrier on both sides, I just want to make sure I'm doing it right the first time so I don't have to come back a year later.

Originally Posted by foxtrot

if the seal behind the FRP is so important it sounds like I should but vapor barrier on it too? But that goes against what I've always been told about totally sealing up a wall.

Vapor barrier goes on the warm side, in this case the outer side of the insulated wall. But isn't it the same as a house were you want the cool side able to breath a bit to remove what moisture leaks in the wall ?

I'm just speaking from what I have seen first hand. FRP holding pockets of water. Not pretty some of it coming down. If you glue it I would suggest rolling on the glue like laminate. Also many homes now use Tyvek on the outside.

Originally Posted by SandShark

My suggestion was sincere. At no time did those thoughts ever cross my mind. I apologize if I gave you the feeling we thought your were a DIY schmuck hack. I wish you all the best with your project.

Thanks its just I got a little thin skinned after getting read the riot act by a few guys at the supply houses when I asked them a few questions and that's why I decided to try you guys here on HVAC-TALK.

if the seal behind the FRP is so important it sounds like I should but vapor barrier on it too? But that goes against what I've always been told about totally sealing up a wall.

Vapor barrier goes on the warm side, in this case the outer side of the insulated wall. But isn't it the same as a house were you want the cool side able to breath a bit to remove what moisture leaks in the wall ?

Originally Posted by foxtrot

SandShark.. rather than chase guys around at the supply houses and get lectures on how I'm taking money out of their pocket, I would rather come on here and ask you guys. After all isn't that the purpose of HVAC-TALK ??

If I repost this in the Pro-section will I get a little more detailed answers from you guys? Not trying to sound terse its just I get the feeling you guys seriously believe I'm some DIY schmuck trying to hack in a cooler.

My suggestion was sincere. At no time did those thoughts ever cross my mind. I apologize if I gave you the feeling we thought your were a DIY schmuck hack. I wish you all the best with your project.

Sounds good so far. What type of fasteners will be holding the ceiling foam then plywood up ? Again you will need to come up with a good seal for the FRP. The plastic divider you typically use will not cut it.

I was planning on putting the vapor barrier (8mil thick vinyl/plastic sheeting) on the back side of the wall (hot side). I can put vapor barrier on the inside also behind the plywood and FRP but I thought you only want vapor barrier on the hot side of the insulated wall other wise if you have it on both sides you will trap water in the wall. Or if on the cool side it would allow moisture to migrate through the insulation from the hot side and condense and fill the wall with water over time.

The ceiling is currently covered in plywood and behind that is 2x6" stud with fiberglass insulation, the building is about 40 years old. I'm going to cover it with the same vapor barrier as the walls then put up about R-30s worth of polystyrene (foamular) foam board then plywood over that with FRP.

[QUOTE=foxtrot;13251491]

Originally Posted by VTP99

Not trying to sound terse its just I get the feeling you guys seriously believe I'm some DIY schmuck trying to hack in a cooler.

I don't think that at all, if that helps

Your staggered wall idea I like. Where exactly are you planning on putting the vapor barrier ? Moisture will be getting in between your FRP seams. You will need to come up with a good seal there. What is the ceiling construction ? Framing wise.

[QUOTE=VTP99;13250321]

Originally Posted by foxtrot

Those studs are not going to have much R value. If you ever saw a thermal image of a houses roof or walls you would see right were the studs are. Maybe steel studs might be better for this.

What I was looking at was staggered stud construction to avoid the issues with the studs heat loss. Using 2x4's there will always be at least 4" of foam to block its heat loss.



SandShark.. rather than chase guys around at the supply houses and get lectures on how I'm taking money out of their pocket, I would rather come on here and ask you guys. After all isn't that the purpose of HVAC-TALK ??

If I repost this in the Pro-section will I get a little more detailed answers from you guys? Not trying to sound terse its just I get the feeling you guys seriously believe I'm some DIY schmuck trying to hack in a cooler.

[QUOTE=foxtrot;13245171]
Then build walls that are 8" thick with staggered stud construction

Those studs are not going to have much R value. If you ever saw a thermal image of a houses roof or walls you would see right were the studs are. Maybe steel studs might be better for this.

Have you gone by and talked to any of the local guys down there? I'm sure they can provide some advice.

I understand the sizing of the equipment, my main concern is if I was overlooking something with the construction of the room itself.

As far as using a panelized box, I wish it were that simple. The problems are the ceiling is 6'11" high, and the room is a L-shape. Both of these mean I would have to get custom panels and it would much more expensive than just building walls and and insulating them.

The other question I had was about a suction accumulator. Being I'm going with a semi-hermetic and a very short suction line (less than 5 feet) since the unit is sitting on the roof right about the cooler, should I order the unit with a suction accumulator? I would prefer not to use one because the memories of sitting on hot roofs dealing with rust out ones or ones that killed the compressor because their oil return hole plugged.

But with a semi-herm not having any shell to take any accidental slugs of refrigerant is it something to consider vs the rust and other issues down the road?

Would it be more economical to purchase a panelized box and assemble it in the space. Less labor and probably less cost than materials.

I dunno - you need insulation to keep the heat out, and a vapor barrier........looks to me like you've addressed both of those things.

Just don't ask me to double check your refrigeration sizing......that's diving way into the DIY end of the pool.