Help me insulate

[FL Guy]

The new tubular building will be installed within two weeks. I found a really good deal on 5 inch Styrofoam 4 x 8 sheets.

The plan is to install 1x4 furring strips across the trusses then screw the 5 inch Styrofoam to the furring strips. This will leave me with a 2.5 inch air gap between the Styrofoam and the bottom of the roof.

I know I’ll be losing approximately 7.5” of “head room”, but with 12’ walls, it’s not a issue.



The walls will have a 1.5” furring strip on the metal to create a air gap with a 1” foam board. So my thought process is the ceiling and the walls will be able to breathe from where the corners of the building come together and it vent towards the peak (ridge area) of the building.

Do I have the installer leave me a 1/2” gap at the peak panels or let the panels touch each other? The ridge cap will have foam inserts over the ribs to keep critters out. Not sure if they will allow air to escape?

By installing the Styrofoam panels with this method, will the siding and roof still condensate?



I’ve also considered spray foam, but 2” of closed cell on walls and roof is $7k for a 940 sf building.

I’ve also read about “flash spray” where it’s 1” of closed cell to help with condensation?



Not sure if I’ll add AC/Heat as this will be a work shop and I just want to be comfortable.



Looking at the building from the front….

The right hand side (south side) has 15’ viburnum bushes 8’ away. The back side (East side) is a wooded lot 8’ away. The left side faces North and the front where the garage doors are face west.

Central Florida is home.

Any ideas is appreciated.

Pics below show what garage will look like as well as bush height and location on property.

 

[Williebeeguy]

Honestly. I've done everything. Pony up for the spray foam. Helps keep everything cool or warm. I would never do anything else after we did it

 

[Merch1]

The new tubular building will be installed within two weeks. I found a really good deal on 5 inch Styrofoam 4 x 8 sheets.

The plan is to install 1x4 furring strips across the trusses then screw the 5 inch Styrofoam to the furring strips. This will leave me with a 2.5 inch air gap between the Styrofoam and the bottom of the roof.

I know I’ll be losing approximately 7.5” of “head room”, but with 12’ walls, it’s not a issue.



The walls will have a 1.5” furring strip on the metal to create a air gap with a 1” foam board. So my thought process is the ceiling and the walls will be able to breathe from where the corners of the building come together and it vent towards the peak (ridge area) of the building.

Do I have the installer leave me a 1/2” gap at the peak panels or let the panels touch each other? The ridge cap will have foam inserts over the ribs to keep critters out. Not sure if they will allow air to escape?

By installing the Styrofoam panels with this method, will the siding and roof still condensate?



I’ve also considered spray foam, but 2” of closed cell on walls and roof is $7k for a 940 sf building.

I’ve also read about “flash spray” where it’s 1” of closed cell to help with condensation?



Not sure if I’ll add AC/Heat as this will be a work shop and I just want to be comfortable.



Looking at the building from the front….

The right hand side (south side) has 15’ viburnum bushes 8’ away. The back side (East side) is a wooded lot 8’ away. The left side faces North and the front where the garage doors are face west.

Central Florida is home.

Any ideas is appreciated.

Pics below show what garage will look like as well as bush height and location on property.

FL as in Harley Davidson?

 

[readhead]

Check with the building company to see if any warranties will be voided if spray foam is installed.

 

[ALinCarolina]

I agree with Williebe. I had my tubular sprayed with closed cell and it has been wonderful. Every seam and every ridge where the panels meet the slab is a leak. If you can afford it you will be pleased.

 

[FL Guy]

No doubt it will. Any "modification" will void the warranty..

Check with the building company to see if any warranties will be voided if spray foam is installed.

 

[FL Guy]

Honestly. I've done everything. Pony up for the spray foam. Helps keep everything cool or warm. I would never do anything else after we did it

I did get ahold of another company on Friday. I said he would foam the building at 1-1.5" roof and walls for $3200. If I went 2" on roof and stayed 1.5 on walls it would be $4200. 2" on everything is $4800...

 

[FL Guy]

I agree with Williebe. I had my tubular sprayed with closed cell and it has been wonderful. Every seam and every ridge where the panels meet the slab is a leak. If you can afford it you will be pleased.

What thickness did you do?

 

[ALinCarolina]

I can't remember for sure and I am not at home for the holiday but I think it was 2 inches. the end wall tubing is 2 in square I think and I know it is covered up flush.

 

[ybnormal]

do the calculation on how the cost of extra insulation vs the cost of cooling and heating, and then compare it to the projected lifespan of the building modified vs 'unmodified' as your building manufacturer tries to b.s. you about spray foam voiding the warranty.
being in central Florida, that means heat, humidity, big thunderstorms to me. I'd rather have an air-conditioned workshop.

 

[billconner]

What are you covering foam with?

 

[Firebrick43]

Spray foam is a bad deal directly on the metal. I have seen several pole barn failures of rust thru. All the R panel manufactures void thier warranty if spray foam is applied.

It also makes panel replacement very difficult as well if needed due to hurricane damage. If you are going to do spray foam place some kind of sheeting/heavy tar paper/house wrap on the structure before putting the panels on to spray to. This will keep the airspace and foam from touching the metal.

Its unfortunate that you didn't get the hat channels to run all your siding vertically. There will be condensation on the metal but given that there is an airspace it should dry fairly quickly and cause no issues if you apply the foam sheets like you were planning. I would do thinner foam sheets personally between the tubes but if you find 5" cheap and don't mind loosing the interior space, it will be better insulated for sure.

Fir on top of the foam and use r panel liner to finish out the inside as well for fire resistance.

 

[FL Guy]

Spray foam is a bad deal directly on the metal. I have seen several pole barn failures of rust thru. All the R panel manufactures void thier warranty if spray foam is applied.

It also makes panel replacement very difficult as well if needed due to hurricane damage. If you are going to do spray foam place some kind of sheeting/heavy tar paper/house wrap on the structure before putting the panels on to spray to. This will keep the airspace and foam from touching the metal.

Its unfortunate that you didn't get the hat channels to run all your siding vertically. There will be condensation on the metal but given that there is an airspace it should dry fairly quickly and cause no issues if you apply the foam sheets like you were planning. I would do thinner foam sheets personally between the tubes but if you find 5" cheap and don't mind loosing the interior space, it will be better insulated for sure.

Fir on top of the foam and use r panel liner to finish out the inside as well for fire resistance.

Apply a vapor barrier between the siding and frame so the foam doesn’t touch the metal?
If I do that, how will the foam stick? The vapor barrier will be held on with a few screws I’m sure, so won’t the weight of the foam bring it down?

 

[Firebrick43]

Apply a vapor barrier between the siding and frame so the foam doesn’t touch the metal?
If I do that, how will the foam stick? The vapor barrier will be held on with a few screws I’m sure, so won’t the weight of the foam bring it down?

No, not a vapor barrier. Foam will stick to a house wrap/tar paper. But it also sticks to the tubes of the structure. Its functionally no different once it hardens than if you glued in foam eps/xps sheets between the tubes.

The house wrap or tar paper will allow any condensation to fall to the ground if it drips onto it from the roof, or leaks from the exterior metals fasteners.

If the foam is sprayed directly onto the metal, the foam holds this water against the metal indefinitely as it cant dry out (lack of air flow) This constant water against the metal is what causes the problems with rusting of it.

There is no such thing as a leak proof exterior fastener sheathing, and its especially true of metal applied horizontally instead of vertically. There eventually will be leaks around the fasteners as the neoprene washers harden and crack.

 

[Williebeeguy]

I did get ahold of another company on Friday. I said he would foam the building at 1-1.5" roof and walls for $3200. If I went 2" on roof and stayed 1.5 on walls it would be $4200. 2" on everything is $4800...

I would do it. Savings on heating will pay for it fast

 

[FL Guy]

I would do it. Savings on heating will pay for it fast

which thickness? I mainly want it to stop condensation.

 

[Williebeeguy]

We did 2" all around. I was told that's kind of the minimum to be useful

 

[billconner]

which thickness? I mainly want it to stop condensation.

Whatever thickness is enough to prevent interior from reaching dew point. Where I am in climate zone 6, it seems to be 2" or more. I would think in a warmer climate, less, and in a colder climate, more.