ReplyI 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.
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My family moved our bakery into a building about 10 years ago that had a room that HAD been a 11' x 11' freezer with 8" urethane foam in all the walls and floor but the previous tenets pulled the evaporator and door and used it for storage.
So when we moved in I installed a new condenser and unit cooler and had a local company install a door and its worked great. But now we are at the point of needed a large amount of freezer space but there is no place outside the building to installed a "knock together" unit.
So the plan is to take the store room next to it and turn it into the cooler and turn the room that is currently the cooler back to a freezer as it was originally.
My plan is to put up a thick 8-10 mil rubber vapor barrier over the walls and ceiling. Then build walls that are 8" thick with staggered stud construction and have the local spray foam (the two part stuff) spray R-30s worth of foam in the walls and cap them with plywood and FRP over that for health code. For the ceiling I was thinking about about 4-6" of foamular styrene paneling and cover it with plywood and FRP also.
For the door I'm going to see if I can get the local company that did the last door to put the one that's on the cooler now on the new cooler and sell me a heated freezer door to put on what will be the freezer.
My questions are mainly about the construction methods. Is there anything I'm overlooking as far as the vapor barrier and insulation method?
I already have a 1hp beacon II R-404 semi-hermetic unit on the cooler that will go on the store room/new cooler that's also 11' x 11' and I'm going to put a 2hp semi-hermetic R-404 beacon II unit on the freezer. Its rated for 9,500 BTUH for -20F SST with the unit cooler rated for 9,500 BTUH with a 10 deg TD.
I know I sound kinda DIY with this post but I went to UTI here in Houston here for HVAC and have had my contracts license with TDLR since 2002 and still carrying insurance. Its just 8 years ago I developed lupus and couldn't deal with the physical demands of HVAC work. So I went back to school and now I teach high school science. The only reason I'm tackling this project is its the parent's bakery and its kinda hard to tell the parents no. It's just after 8 years I'm wanting to make sure I'm not overlooking something that will bite me in the rear later.
So is there anything I'm overlooking with the construction aspect of the room?
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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.
"The problem is the average person isn’t tuned in to lifelong learning, or going to seminars and so forth. If the information is not on television, and it’s not in the movies they watch, and it’s not in the few books that they buy, they don’t get it" - Jack Canfield
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Would it be more economical to purchase a panelized box and assemble it in the space. Less labor and probably less cost than materials.
In GOD We Trust
Professional Member
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?
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Have you gone by and talked to any of the local guys down there? I'm sure they can provide some advice.
With your chrome heart shining in the sun, long may you run.
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[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.
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[QUOTE=VTP99;13250321]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.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.
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.
Global Moderator
[QUOTE=foxtrot;13251491]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.
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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.
Global Moderator
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.
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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.
With your chrome heart shining in the sun, long may you run.
Professional Member
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 ?
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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.
Global Moderator
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.
Professional Member
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.
Global Moderator
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.
Professional Member*
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.
With your chrome heart shining in the sun, long may you run.
Professional Member
use a good TXV and set up the system to pump down on shut off and you shouldn't get any slugs of liquid.
Professional Member
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.
Professional Member*
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.
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