Commercial roofing- advise me

I need some advice on products and techniques for a commercial re-roof. 

I've spent my life managing construction projects and ensuring quality installations, but I am usually working inside someone else's specs.  This time, I am the guy who gets to write the spec. 

Uggh.

Anyway, the building is a medical facility in SC. Lots of sun exposure.  It's not on the coast, but still in high wind area (Columbia SC). 

Its about 60,000 SF of roof area. The existing roof is a Carlisle EPDM single ply roof (no ballast). Flat roof. Lots of penetrations, flashings, and curbs. 

The existing roof is not in bad condition, but it has a few leaks. Nearing the end of it's warranted lifespan. It's a 17 year old building- original roof. Owners would like to consider a reroof before significant problems arise. 

So, what are my options?  Is there a product that can be put over the existing with satisfactory results?  Is it better to tear off and start over?  Are there better products?  Any suggested upgrades?  Reflective roofs, etc?  Best for future maintenance?

Anyone in the SE selling products like this?

How about manufacturers?  Additional insulation?

Looking for an education in something I should already know...

I'm bumping this. 

Some of you MUST have some insight!

The roofing specs we use tend to vary a lot depending on each client, but our generic EDPM roofing spec seems to be based on this.  

Tear it all off, down to the deck. (Good luck with the rain)

Replace with Siplast lightweight insulating concrete and SBS modified bituminous roof. Huge uplift strength, redundancy by multiple layers system.

​​​​​​I'm not a fan of single ply roofs. But they are cheaper.

In reply to SVreX :

I'm no pro, but we had our adjoined buildings in IL reroofed after we bought them. Since one was 2-stories, and the other 3, we did them a year apart. Each roof is ~22'x70' with a slight pitch. 

On the 2-story side we did first, I had the local roofer guy put down rolled rubber. It was ~$2k about 9-years ago, and has held up fine, however the quoted lifespan was about 10-years. 

On the 3-story side I hired a professional commercial roofer and went with a white membrane product that was about 3x as thick with a lifespan of 25+ years. It was about $4k and worth every penny. 

The rubber roof is basically like having a bicycle inner tube stretched over the roof, and feels about as (non)durable. The white membrane is rigid and I'd have no worries walking on it or even putting a ladder up there. 

Sorry for the lack of specifics, and not sure this will help at all, but in our case the better/more expensive product seems well worth the added cost. 

https://doa.wi.gov/Pages/DoingBusiness/MasterSpec_Div7.aspx

Fun fact: The State of Wisconsin has all of their master specs free for everyone to use. Obviously things are different in SC but it's a place to start. I couldn't find an equivalent website for SC.

I'm going the opposite way from OHSCR.  I like adhered single-ply roofs, because they are easy to install so you are not as mechanic-dependent.  Plus they are relatively easy to diagnose and fix when you do have leaks.  Plus plus, there are prefabricated flashing solutions available for almost anything you need to flash around.

If it is a medical facility, it's not going to be easy to do a complete tear-off, particularly in springtime when weather is unpredictable.  Have some cores done to check for water in the insulation at various spots around the building.  If there is any evidence, then I suggest a tearoff.  But if it is dry, I say leave it.

If the building it 17 years old, it probably has decent insulation for the area.  It could always use more, of course.

I would put down 2" of XPS insulation over the existing roof with 1/2" fiber-faced gypsum roofing board over that, mechanically fastened to the deck.  Then put an .045 reinforced or .060 unrefinforced white-coated EPDM membrane over the roofing board, full adhered.  If you don't have the available freeboard at your perimeter flashing and curbs to add the insulation, reduce it or skip it and just go with the roofing board.

You can also use TPO membrane; I've used both, and it's inherently lighter in color instead of coated.  Both install similarly. It’s really down to what’s more common in your region.

I wouldn't hesitate to reach out to the Carlisle rep and get their recommendation.  I've had good luck with their support.

Avoiding the tear-off is a definite advantage. 

We see 800 patients a day. A full facility shutdown would definitely be impossible. The financial impact would exceed $1 million per day. 

Of course, we can stage it. But a quality roof-over would be my choice rather than a tear-off. 

I'm sorry I can't offer much advice. But we switched from a ballasted built-up roof to a single ply white Sarnafil roof, coupled with tapered insulation, on our flat room. Our utility usage dropped an amazing amount. I'm sure your insulation is better than ours was already since our building is almost 100 years old, but the difference in utility costs was really striking.

We've been happy with the Sarnafil roof. We've had some maintenance required but it's been up there for a decade or so, and the main problems have been failings of the surrounding structure and not the roofing system. And they were very minor, easily fixed.

How many of these do you think it would take?

x2 for Duke's comments.  I've installed a couple million SF of TPO on warehouses and for the most part they are good roofing systems after the first weather cycle.  We always used Firestone.  They currently have a TPO system with a 30-yr warranty and is an 80-mil thickness.  Some systems are fully adhered, others are mechanically fastened.  Building codes and uplift requirements may dictate one system over another.

http://firestonebpco.com/roofing/tpo-roofing-systems/platinum-tpo-roofing-systems/

There are a lot of options for this facility. Medical buildings can be simple like regular offices or super complex if they house lots of moderately sized equipment. If they have a lot of big equipment then the roof replacement with a high end system would actually be one of their lower investments. I work on laboratories where some of our equipment can get easily to a quarter million. So usually the roof gets a good looking at before we put it in. Ask your customer if they are seeking any carbon footprint or LEED or other environmental goals, as it may limit you to those type of high performance systems. One recent trend is channeling roof water to pollinator gardens. Not sure of how much you are responsible for, but if you own the whole project , plan to rebalance the HVAC due to the increased thermal control the roof is likely to provide. 

I assume you have someone with structural knowledge to help with the column loadings. Being a Medical facility, if they have renovated recently a lot of equipment is now being hung from ceiling tracks vs floor. Thus the as built loading of the columns would indicate numbers lower than current loading. That may decide whether you can just layer more load on top vs replace with new. As you own the whole thing this time, as dculberson mentioned, make sure the existing structure that will remain would get updated to properly match with any roofing choice you make. 

If you want you can ask a Sika/Carlisle/GAF/Firestone or another manufacturer to offer some application engineering support. Some offer it some don't depending on the volume of the sale and past work relationships. They would probably need to understand current state of structural loading before they answer. I tend to find most of the prime contractors I deal with on mid to big jobs just get their roofing engineering and submittal information directly from the manufacturers. 

Drilling a core and SUCCESSFULLY sealing it is a good idea to see what internal work you would encounter with a removal. Especially if they don't have good as built drawings or photos from construction. 

If you elect to go single ply, look for membranes that have hot air welded seams. These usually have compatible coated metal flashing available. It's great to hot air weld the membrane to the flashing for tricky details.

I do not like EPDM because it's seams are glued. I may be nuts but thats my preference to avoid glued stuff. TPO, PVC and hybrids (Fibertite is a good one) are all hot air welded membranes. 

Just make sure you glue down some walk pads so the foot traffic on the membrane is kept to a minimum.

@ the op. Call me tomorrow if you want to chat. I have been designing roofs professionally for a long long time. I was vp of a engineering firm for years and now am the president and owner of a architectural firm that specializes in this stuff. 

There are a lot of questions that need to be answered before recommending a system. Nothing crazy just need to know some specifics about the building.  For those with a bent towards a particular system I will tell you that there are many good systems out there it is just that they are all not great on all buildings. 

Then there is code.  I assume they are using the IBC 2015?  Or in this case it would be the IEBC.  There have been changes to the code with respect to the IEBC and the IEC.  Another thing is this building may required controlled construction. You should look at the code.   Not a big deal but the owner should be made aware of this sooner rather than later if it is needed.  

My company: ehadesign.com. 

OHSCrifle said:

I do not like EPDM because it's seams are glued. I may be nuts but thats my preference to avoid glued stuff. TPO, PVC and hybrids (Fibertite is a good one) are all hot air welded membranes.

Heh, and again, I'm the opposite.  I like glued seams.  I seem to have better luck with them, at least given the roofers around here.

In reply to OHSCrifle :

TPO has truly terrible reviews. The only good thing people seem to be able to say about it is that it is cheap, and white. 

dean1484 said:

@ the op. Call me tomorrow if you want to chat. I have been designing roofs professionally for a long long time. I was vp of a engineering firm for years and now am the president and owner of a architectural firm that specializes in this stuff. 

There are a lot of questions that need to be answered before recommending a system. Nothing crazy just need to know some specifics about the building.  For those with a bent towards a particular system I will tell you that there are many good systems out there it is just that they are all not great on all buildings. 

Then there is code.  I assume they are using the IBC 2015?  Or in this case it would be the IEBC.  There have been changes to the code with respect to the IEBC and the IEC.  Another thing is this building may required controlled construction. You should look at the code.   Not a big deal but the owner should be made aware of this sooner rather than later if it is needed.  

My company: ehadesign.com. 

Hi Dean:

Tried to call- did not get through. Feel free to call me any time. 

Thanks!

Paul

Just saw this.  It was great chatting with you. If you need more info you know where to find me!!  Hope the info I gave you was helpfull. 

Oh I looked up the code and you are on the IBC/IEBC 2012 and you are using the IEC 2009.

Duke said:

OHSCrifle said:

I do not like EPDM because it's seams are glued. I may be nuts but thats my preference to avoid glued stuff. TPO, PVC and hybrids (Fibertite is a good one) are all hot air welded membranes.

Heh, and again, I'm the opposite.  I like glued seams.  I seem to have better luck with them, at least given the roofers around here.

The biggest issue with thermo plastic and welded seams is that every sheet welds differently.  So if a roofer has experience putting down PVC and then just jumps in and starts welding a TPO system thinking it is going to be the same the seams will not be welded properly.  Then the roofer will say that the TPO is a crappy product when in fact he is at fault for not learning how to install it properly.  99.9 percent of roofing problems are applicator error and most of that is just because the roofer does not know that they are doing it wrong.  They wrongly assume that because we do it this way with this system and this product we can do it the same for all the other similar products.  There are allot of roofers out there that hate me because I have proved that they did it wrong. 

I thought one of the benefits of a ballasted roof is it protects whatever membrane that's used from UV damage.