# Florida Building Code, is there a minimum sill height for a sliding glass door ?



## joer00 (May 5, 2022)

My supplier (PGT) notes in the installation instruction that the sill height (inside) depends on local code. However I can't find any such requirements in the code.
Some photos I found on the net show indeed an "ugly" high sill inside where you would need to lift your feet to get out of the door.

I want to have the sill flush with my finished floor for looks and convenience. Is this not allowed ? Somebody told me it has to do with water coming in but my outside terrace is a wood deck with natural drain and covered partly by a roof.


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## fatboy (May 5, 2022)

The building code does not specify a minimum sill height. Hell, make it flat. Unless the Florida Codes have some weird requirement. Same type of thing in snow country, folks think you need to lower the landing, so your door doesn't freeze shut.


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## brokenkeys (May 6, 2022)

There's a code required test for wind driven rain, which sliders (and most other doors) fail without high sills. Code doesn't care what the terrace is made of. How big is the roof? 

If you have an overhead ratio greater than or equal to 1 (or in other words if your terrace is 10' wide and has a 10' [or greater] roof) then the water infiltration requirement is exempted, and you can use a flush sill. 

If not, then you have to use a non-flush sill to meet the water infiltration requirement. The sill height depends on the wind pressures and could potentially be up to 4" tall for a PGT, if your pressures are high enough. Talk to your installer/ designer/ whomever about the NOA's and wind pressures. If you have your wind pressures you can look up the required sill height in the NOA. 


Yes, it is ugly and even worse it often doesn't meet FHA or ADA so, us architects, have to figure out how to meet the requirement without violating other codes and as a reward we get yelled at by owners/ developers because of the cost.


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## steveray (May 6, 2022)

Where is the test for wind driven rain?


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## jar546 (May 6, 2022)

brokenkeys said:


> There's a code required test for wind driven rain, which sliders (and most other doors) fail without high sills. Code doesn't care what the terrace is made of. How big is the roof?
> 
> If you have an overhead ratio greater than or equal to 1 (or in other words if your terrace is 10' wide and has a 10' [or greater] roof) then the water infiltration requirement is exempted, and you can use a flush sill.
> 
> ...


We've had issues with this in non-ADA condos where the unit owner became wheelchair bound, paid to replace the slider to the balcony with impact/hurricane rated and then complained about the curb.  Water intrusion into a building on the beach is more important to the structure and safety of the residents, unfortunately.


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## brokenkeys (May 6, 2022)

I believe the test itself is a TAS or test protocol and is referenced somewhere. Ch 16 possibly? I don't really get into the testing, just scouring through NOA's / designing around the limitations of the products.

Picking a random PGT slider as an example: https://www.miamidade.gov/building/library/productcontrol/noa/20042909.pdf. Starting on page 11 of the NOA outlines the pressures, and how much they reduce with lower sills (starts at +/- 90 but cuts down to 46 with the low sill).

Also, a correction to my above statement; it's not based on the terrace width but the height (10' height requires a 10' overhang). There are diagrams in the linked NOA explaining it better.


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## fatboy (May 6, 2022)

jar546 said:


> We've had issues with this in non-ADA condos where the unit owner became wheelchair bound, paid to replace the slider to the balcony with impact/hurricane rated and then complained about the curb.  Water intrusion into a building on the beach is more important to the structure and safety of the residents, unfortunately.


So it is a Florida thing......or coastal anyway.


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## steveray (May 6, 2022)




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## jar546 (May 6, 2022)

fatboy said:


> So it is a Florida thing......or coastal anyway.


It's a wind zone thing.  Just like most, if not all of the country not on the coast completely ignore wind pressure rating of windows and only look at energy compliance.  If you are in a 115mph wind zone, per the IRC/IBC, the wind pressures apply to windows, yet who outside of coastal areas check it, even though you should be.  Replacement windows, in particular are blown off more than anything and rarely even permitted.


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## brokenkeys (May 6, 2022)

Most doors have language buried somewhere in the NOA/ Florida product approval about not being approved for water infiltration or if water infiltration is required you have to use the giant non-ADA threshold.

Similar to JAR's note about everyone being concerned about energy for windows; the big concern for storefront door thresholds is ADA. The problem is most ADA storefront door thresholds don't meet water infiltration. There are very few storefront door manuf. that meet water infiltration AND ADA. 3 that I know of and two use wonky work arounds such as YKK's ramp on page 13 here: https://www.floridabuilding.org/upload/PR_Instl_Docs/FL16554_R10_II_YKK020 SS 2021-10-11.pdf. It looks just as bad in real life.


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## redeyedfly (May 6, 2022)

brokenkeys said:


> Most doors have language buried somewhere in the NOA/ Florida product approval about not being approved for water infiltration or if water infiltration is required you have to use the giant non-ADA threshold.
> 
> Similar to JAR's note about everyone being concerned about energy for windows; the big concern for storefront door thresholds is ADA. The problem is most ADA storefront door thresholds don't meet water infiltration. There are very few storefront door manuf. that meet water infiltration AND ADA. 3 that I know of and two use wonky work arounds such as YKK's ramp on page 13 here: https://www.floridabuilding.org/upload/PR_Instl_Docs/FL16554_R10_II_YKK020 SS 2021-10-11.pdf. It looks just as bad in real life.


The threshold on p.13 does not meet ADA (or IBC).  Max slope for a landing on either side of the door is 1:48.


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## redeyedfly (May 6, 2022)

jar546 said:


> It's a wind zone thing.  Just like most, if not all of the country not on the coast completely ignore wind pressure rating of windows and only look at energy compliance.  If you are in a 115mph wind zone, per the IRC/IBC, the wind pressures apply to windows, yet who outside of coastal areas check it, even though you should be.  Replacement windows, in particular are blown off more than anything and rarely even permitted.


You check it in high rise, but otherwise, yeah, no one cares.


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## jar546 (May 6, 2022)

redeyedfly said:


> You check it in high rise, but otherwise, yeah, no one cares.


We check in in single family homes and every building with a window.  You should care because it is part of the code and therefore your job


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## redeyedfly (May 8, 2022)

jar546 said:


> We check in in single family homes and every building with a window.  You should care because it is part of the code and therefore your job


Maybe your job, not mine.


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## jar546 (May 9, 2022)

redeyedfly said:


> Maybe your job, not mine.


So you pick and choose the codes you enforce?  Who decides that?


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## redeyedfly (May 9, 2022)

I don't enforce codes.


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## ICE (May 9, 2022)

redeyedfly said:


> I don't enforce codes.


If your occupation involves conceptualizing, designing, constructing or is, in any way, related to the built environment you, by default, enforce codes.  Carpenters, electricians, plumbers and tin knockers enforce code whether they know it or not.


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## tmurray (May 9, 2022)

Is the AAMA/WDMA/CSA A440/I.S.2/101 standard referenced for the water penetration requirements? That is what we use (along with the Canadian supplement).


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## brokenkeys (May 9, 2022)

tmurray said:


> Is the AAMA/WDMA/CSA A440/I.S.2/101 standard referenced for the water penetration requirements? That is what we use (along with the Canadian supplement).



FBC 16 & 17 and the TAS's refer to AAMA/ WDMA, etc. Example;
1709.5.1Exterior windows and doors.​Exterior windows and sliding doors shall be tested and labeled as conforming to AAMA/WDMA/CSA101/I.S.2/A440 or TAS 202 (HVHZ shall comply with TAS 202 and ASTM E1300 or Section 2404). Exterior side-hinged doors shall be tested and labeled as conforming to AAMA/WDMA/CSA101/I.S.2/A440 or comply with Section 1709.5.2......



redeyedfly said:


> The threshold on p.13 does not meet ADA (or IBC).  Max slope for a landing on either side of the door is 1:48.


Like I said it's wonky. For most doors there is no option; if you have a 3" sill then you have a 3" sill.


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## redeyedfly (May 9, 2022)

brokenkeys said:


> Like I said it's wonky. For most doors there is no option; if you have a 3" sill then you have a 3" sill.


Every inspector I've ever met would tell me that's a design problem, not a code problem.  In new construction that threshold will not pass 100% of the time. I really can only see these in renovations where it's the best you can do.


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## tmurray (May 10, 2022)

brokenkeys said:


> FBC 16 & 17 and the TAS's refer to AAMA/ WDMA, etc. Example;
> 1709.5.1Exterior windows and doors.​Exterior windows and sliding doors shall be tested and labeled as conforming to AAMA/WDMA/CSA101/I.S.2/A440 or TAS 202 (HVHZ shall comply with TAS 202 and ASTM E1300 or Section 2404). Exterior side-hinged doors shall be tested and labeled as conforming to AAMA/WDMA/CSA101/I.S.2/A440 or comply with Section 1709.5.2......


OK, so here, they would need to hit 400 Pascals for the water penetration, which they can do with an enhanced sill. We have the issue fairly often when they try to use a regular sill and we fail the door because it doesn't meet the performance requirements. Luckily we ask for this information at the permit review phase, so it gives the contractor and the supplier a chance to correct things early, saving everyone money.


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