# Flat roofs...remove or recover old roof???



## 232323 (Mar 31, 2008)

What criteria do you guys use when deciding whether to remove or simply recover an existing built-up roof with a membrane? Obviously, if the deck is damaged or saturated, the choice is obvious, but what about the rest of the jobs where it isn't so clear cut. With the light weight membranes, I can't see where weight should ever be an issue.....


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## 4 seasons (Jan 4, 2010)

In my opinion it is always better to remove the old roof. Even if it is lying perfectly flat, draining properly and lightweight it is impossible to really know what's underneath. Their could be rot under there and you may never know.
I will typically only install a second layer when a customer is in a tough spot...


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## WNYcarpenter (Mar 2, 2007)

I'm not sure exactly what you're asking....

I do a couple dozen EPDM inspections in the fall and spring. I go around with cleaner and a bag of rags and wipe down everything, especially the details. Check the facia and other wood work and typically re caulk everything. 

The worst areas always seem to be at the roof edges and around chimneys. Occasionally I'll find a small hole that I'll clean, prime and patch.

When I find a soft spot I'll cut the membrane back to solid decking, repair and glue down a new piece over lapping 6", or whatever will look neatest.


























I guess it all depends on the size of the roof....


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## MAULEMALL (May 16, 2010)

Thats a nice looking repair... Do you use a termination bar on the chimney?


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## WNYcarpenter (Mar 2, 2007)

MAULEMALL said:


> Thats a nice looking repair... Do you use a termination bar on the chimney?


Thanks!

I counter flashed with metal starting at the course above where the rubber stops. 

I still need to tuck point the whole thing, but the temps got too cold. That's why you see all the dust (bagged it and tied it off 'till spring)...I did make at least one mistake I'm sure of. I should have cleaned the seams again before I caulked. 


I still don't think I completely understand the OP's question......


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## 1985gt (Dec 10, 2010)

90% of the time tear off. The problem with recovers is you don't know exactly what your recovering. A lot of times you are recovering trapped moisture in the Bur or other type of roof. Plus what others have said about being able to see the deck is in good shape.


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## RoofSales (Dec 7, 2011)

Obviously you need to make sure whatever you do is in-line with local building codes along with any special insurance requirements that might be present.

There are 3 'universal' things I use to determine if I need to tear-off or if a recover is possible:

*1. Two or More Existing Roof Systems in Place:* Never want to have more than two systems in place. If two are already in place you would, at a minimum, need to do a partial tear-off.

*2. Wet Insulation:* Never cover over wet insulation. If you think roof vents will dry out saturated insulation you may have been around too much bonding adhesive!

*3. Weight Loads:* This really comes into play when you are dealing with re-ballasts. However, some roof systems may already be too heavy and would need to be torn-off just to be in compliance.


A final point to consider (very important) is your proposed attachment method. For example. Let's say the existing structural deck is pre-cast concrete and the roof is made up of perlite insulation and a 3-ply built-up roof with gravel. If you wanted to recover you'd have some additional testing to do... You don't want to fasten into this type of deck for issues with long-term sustainability (can have entirely different thread on this) which means you would need to fully adhere. To fully adhere you'd likely need to use a low-rise foam adhesive (OlyBond) but you'd still need to have some third-party testing done to make sure you get adequate wind-uplift. 

Ofcourse, in the above example, you could also install ballast. But I'm making the assumption that price is the driving factor for a recover. If the ballast isn't already in place it would likely be more expensive than a tear-off.

Just my thoughts!

-Eric


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## 1985gt (Dec 10, 2010)

RoofYourWorld said:


> A final point to consider (very important) is your proposed attachment method. For example. Let's say the existing structural deck is pre-cast concrete and the roof is made up of perlite insulation and a 3-ply built-up roof with gravel. If you wanted to recover you'd have some additional testing to do... You don't want to fasten into this type of deck for issues with long-term sustainability (can have entirely different thread on this) which means you would need to fully adhere. To fully adhere you'd likely need to use a low-rise foam adhesive (OlyBond) but you'd still need to have some third-party testing done to make sure you get adequate wind-uplift.
> 
> 
> -Eric


So you have never used mechanical attachment to concrete decks? Pre-cast or poured?


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## RoofSales (Dec 7, 2011)

1985gt said:


> So you have never used mechanical attachment to concrete decks? Pre-cast or poured?


I've fastened into both. Other than being extremely loud and intrusive for customers (hospitals, nursing homes, etc) I don't have too many issues with fastening into poured - although I would prefer to fasten the board then adhere the membrane in a recover situation.

With pre-cast there are just too many things that can go wrong.


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## 1985gt (Dec 10, 2010)

RoofYourWorld said:


> I've fastened into both. Other than being extremely loud and intrusive for customers (hospitals, nursing homes, etc) I don't have too many issues with fastening into poured - although I would prefer to fasten the board then adhere the membrane in a recover situation.
> 
> With pre-cast there are just too many things that can go wrong.


Loud and intrusive is an understatement. We have never had problems with fastening in to precast. We try to avoid fastening to concrete when ever possible. Some warranty's require it though.


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## RoofSales (Dec 7, 2011)

1985gt said:


> Some warranty's require it though.


Which manufacturer? Are there not adhered options that could also be warranted?


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## 1985gt (Dec 10, 2010)

30 year EPDM. ISO adhesive can only be used on GYp and Tech decks.


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## RoofSales (Dec 7, 2011)

1985gt said:


> 30 year EPDM. ISO adhesive can only be used on GYp and Tech decks.


Wasn't considering the 30 year material warranty. Guess it is all up to the customer.


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## 1985gt (Dec 10, 2010)

30 year total system but yeah, it's happened more then once with us. In fact I believe the 20 year is the same.


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## RoofSales (Dec 7, 2011)

30 year labor warranty? Is it pro-rated after a certain point? Would like to see a copy of it.


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## 1985gt (Dec 10, 2010)

http://www.versico.com/documents/reslib/vsw_1_rev4-11.pdf

Versico


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## RoofSales (Dec 7, 2011)

But is there a warranty which outlines the 30 year coverage (what is and is not covered, fees to maintain, pro-rated times, etc...)?

I'm legitimately curious, not trying to nitpick.


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## 1985gt (Dec 10, 2010)

Same warranty forum, just fill in the blank for x amount of years. 

Here is a warranty brochure

http://www.versico.com/documents/reslib/602016_VersiGard_30_Year_Warranty6_08.pdf

Heres one from Carlisle

Fill in the blanks for years and wind.

http://www.carlislesyntec.com/default.aspx?page=view&mode=media&contentID=1441&frompage=search&category=96&mediatype=literature


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## rooffix (Feb 11, 2012)

I recently did a job using emulsion, fabric and elastomeric coating over older torch down. It came out pretty good, and the manufacturer warrantied the job for ten years.


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## RoofSales (Dec 7, 2011)

rooffix said:


> I recently did a job using emulsion, fabric and elastomeric coating over older torch down. It came out pretty good, and the manufacturer warrantied the job for ten years.


How many projects like this have you done?


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