# Shingle Over Or Remove/replace?



## BullDogg (Oct 11, 2007)

My first time on a forum like this.

I am just starting to research a DIY job on my primary home. The roof has not been replaced since the home was built in 1989. Although no leaks it is looking faded and the asphault is pebbling off. 

The home is one story hip and gable roof over 3990 sqft of house (big order for DIY, I know). Its been many years since I assisted in singling a roof, however it was not difficult then using just shingle, hammer and nails. I do have three teen age boys who will be "eager" to help...well, they'll help anyway. The home is in the Tampa Bay, Florida area.

For the more experienced the question is whether I should shingle over the existing roof, or remove and replace? What are some common first overlooks for estimating the job in both expense and materials? Any other "by the ways" to help?

Thanks.

BullDogg


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## adawg (Sep 28, 2007)

I've been told that 2nd layers build excess heat and do not allow a proper cooling cycle. THis means the new shingles will age prematurely and need to be replaced much sooner than if you did a complete tear off and re-roof. But, I am not a roofer...


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## jogr (Jul 24, 2007)

You have three teenage boys for tearoff so that's easy!

I hate tearing off shingles but I hate shingle overs more. I'm sure they can be done ok but I always felt like the roof wouldn't look as nice, hold up as long - and why carry all that extra weight on your roof (I guess you don't have to worry about snow load there).

Measure the roof carefully, don't forget to account for shingles for the ridge. Plan on finding some roof sheathing that needs replacement. Use architectural (dimensional) shingles instead of 3 tab. They look better, go on easier and seem to hold up better.

That's a mighty big roof. Tear off and reroof a section at a time. Start small until you get a feel for how much you can do at a time. I imagine it rains pretty frequently there and you don't want tearoff to get ahead of what you can shingle before the next rain. Make sure you tarp the transitions between new and old really well as you work your way around the house.

Make sure you use those boys! They will never forget helping Dad with the roof.


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## Mart (Aug 20, 2007)

Be careful about shingling over. I don't know if that will affect the warrenty of your shingles or not. Check it out!


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## Ed the Roofer (Jan 27, 2007)

The age of your roof and the probable inherent brittlness will likely cause secured nail fastening detachment.

The more brittle the underlying roof system is, the more chances you have for the nails to move laterally, sort of like a toggle affect. This will eventually lead to nail displacement and loose shingles.

Additionally, the trapped air between the old roofing shingles and the new roofing system will allow contained areas of heat pockets, or heat sumps as I have elsewhere heard it described. This additional trapped heat will significantly cause the new roof system to fail prematurely. 

As a rule of thumb, I believe that you should factor in a minimum of a 25 % decrease in shingle life longetivity for each additional layer of roofing shingles applied.

Further, due to this premature failure and the necessity to do the roof over again in less than 15 years, you will not have the personal desire and the availability of the sons to assist you in your tear-off endeavors.

Also, the additional packing along the eave and gabled edges is unsightly and will reduce the ROI of you home if you decide to place it on the market.

Finally, your roof square footage will be a major undertaking and you should allow for over a months worth of weekends to miss out on other essential family activities. 

Who amongst your family members has any day to day knowledge of the proper and correct application methods and will adhere to them accordingly?

What will you do if the weather takes a turn for the worse, while stripping off the old roofing materials?

How much carpentry expertice do any of you have in the event that some of the deck sheathing needs replacement?

This is a very large project for a DIY with your kids.

Ed


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## Big Bob (Jul 27, 2007)

Roof over is bad practice anywhere in FL. I am not aware of any manufacturers warranty on a roof over. Ed has detailed many of the reasons above. Besides that they look like dodo. FL humidity is just too tough on roofing materials to allow roof overs except as a foolish option of last resort.:no:


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## skymaster (Jun 6, 2007)

4o squares, a tearoff, sheathing repair,replacement, caps , debris removal, 

DIY? Not this one. REALLY call a roofing contractor, get a beer, sit in the pool and watch em work. Roofing is NOT an enjoyable sport. 
No insult intended, just loading the shingles is an absolutely miserable bear of a job. 3 tabs are about 125 lbs per square or more. 40 sq, probably 5000 lbs or more, plus paper, nails etc in FLA heat nah ya dont wanna go there
JackM


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## Docfletcher (Aug 1, 2007)

Don't put your children or yourself at risk. Besides any mistakes the kids make you most likely won't catch. :yes:


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## BullDogg (Oct 11, 2007)

*thanks*

To all -

This is what is so great about forums like this. All suggestions and comments have given me pause to reconsider my initial plan. I had not considered issues of warranty or heat build-up with an shingle-over. I'll get some more job estimates form area roofers. Thanks for your help.

All the best - BullDogg


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## the roofing god (Aug 2, 2007)

3-tabs(25 yr)start at 235 lb.s per square,you need to strip it check the decking,tape all the plywood seams,install eave protection,felt,flashings,ventilation etc,and dependent on location a metal roof may be a far better choice for you


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## Ed the Roofer (Jan 27, 2007)

TRG.

I had to tape the vertical seams of the OSB overlay on a skip sheathing job once. The OSB was specified by the GC, so that was not my choice.

We did the roof in December or January and it looked perfectly flat. Th elderly lady HO refused to add additional ventilation.

3 months later, when the spring warmth arrived, the 4 foot vertical seams in many locations were telegraphing through the shingles.

Upon going there to check it out and removing the 3=tabs from the multiple 4 foot areas, we found that the felt paper had ballooned up on these joints. Certainteed advised us after checking it out, that the lack of additional exhaust ventilation was the culprit.

Is this the reason you tape the seams?

If not, what other reasons do you list for that necessity?

Thanks,

Ed


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## the roofing god (Aug 2, 2007)

actually,I don`t do it,but it is code now in florida,which is where the poster said he lives,also shingles take a beating there from the salt air,that`s why I said he should consider metal


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## Ed the Roofer (Jan 27, 2007)

On the one I had the problems with, after we removed the shingles and cut the bumps out of the felt paper, we installed duct tape on the vertical seams and then slap stapled it down also. Then we re-applied new felt and the shingles.

It is now about 6 years later and they are still doing fine.

Ed


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## the roofing god (Aug 2, 2007)

this is in regards to the seam tape required in florida on plywood seams: *
Mitigation Manual" referenced therein​For the purposes of this guideline the code sections specified will be from the Hurricane Mitigation Retrofit Manual.​**I. Supplemental Fasteners and Secondary Water Barrier​* 
*A. Trigger:​*​When a roof on an existing site-built, single family residential structure is replaced. [According to the 2004 Florida Building Code (Section 1502 Definitions): ROOF REPLACEMENT: The process of removing the existing roof covering, repairing any damaged substrate and installing a new roof covering.] 
​
*B. Requirements:​*​1. Roof deck attachment and fasteners shall be strengthened and corrected as required by section 201.1. 

2. A secondary water barrier shall be provided as required by section 201.2. Self-adhering polymer modified bitumen tape or sheets (peel and stick products) must comply with ASTM D1970 ​*C. Guidelines​*Q. Is there a required inspection (or affidavit certification) for the supplemental fasteners? 
A. Yes 
Q. Who can perform this inspection (or affidavit certification)? 
A. Florida Professional Engineer, Registered Architect, Licensed General Contractor, Building Contractor, Residential Contractor, Roofing Contractor or persons certified in the structural discipline under FS 468. 
Q. Can existing sheathing fasteners be used to satisfy the supplemental requirement in Table 201.1 where wind speed is greater than 110 mph? 
A. Only if the existing fasteners are 8d clipped head, round head, or ring shank and spaced at 6" or less on center. 
Q. What type of fasteners must be installed to satisfy the supplemental requirement in Table 201.1? 
A. Supplemental fasteners shall be 8d ring shank nails with round heads and the minimum dimensions as specified in 201.1. 
Q. Are the enhanced fastener requirements and secondary water barrier required on new construction? 
A. No. 
Q. Is there a required inspection (or affidavit certification) for the secondary water barrier? 
A. Yes 
Q. Who can perform this inspection (or affidavit certification)? 
A. Florida Professional Engineer, Registered Architect, Licensed General Contractor, Building Contractor, Residential Contractor, Roofing Contractor or persons certified in the structural discipline under FS 468. 
Q. Can self-adhering polymer modified bitumen (peel & stick) be applied directly to the roof sheathing in the HVHZ as well? 
A. Yes for the purposes of complying with these secondary waterproofing requirements only. (Subject to local approval) 
Q. What is the minimum thickness of self-adhering polymer modified bitumen that can be installed?​A. A minimum of 40 mil is required, Per ASTM D 1970. 
 forget about DIY IN Florida:wink:


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## skymaster (Jun 6, 2007)

RoofingGod: under guidelines: Q are the supplemental fastners and secondary water required on NEW CONSTRUCTION?
Answer is NO???????????? WTF????????????? SAY WHAT?????????
No wonder FLA has the rep it has earned.:no:


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## the roofing god (Aug 2, 2007)

I KNOW ,I THOUGHT THE SAME THING


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## Ed the Roofer (Jan 27, 2007)

That guide was specifically for existing homes.

Is there possibly another one geared specifically towards new construction?

Ed


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## the roofing god (Aug 2, 2007)

DIFFERENT REQUIREMENTS ???IT WAS WHAT I SAID IT WAS ,After all that was the topic subject,Go to my home away from home to ask the new construction question:wink:


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## Ed the Roofer (Jan 27, 2007)

skymaster said:


> RoofingGod: under guidelines: Q are the supplemental fastners and secondary water required on NEW CONSTRUCTION?
> Answer is NO???????????? WTF????????????? SAY WHAT?????????
> No wonder FLA has the rep it has earned.:no:


TRG,

It was because of this post. You should read through and see why a certain comment is made before getting offended and taking it as off topic to the thread. Be cool, especially with the caps, sort of like yelling your distate at the question. Huh? 

Ed


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## the roofing god (Aug 2, 2007)

certain parts of my p-word require caps,so if `I`M IN CAPS and switch to lower case ,that`s usually the reason(not quite the typist you are,though my spelling`s better:laughing: ,SO i DON`T WANT TO RE-TYPE ANYTHING),when I tell you to post the question at my home,I figure you know what I mean as there are more floridians there to answer the question for you,ya big dummy,I`m in new york,you should be happy I knew as much as I do about it,I stated that my answer was on thread ,not that you were off thread,but I suggested a way for you to get all the pertinent answers w/out offending this site,and here I thought I was being thoughtful--skymaster q+a was self contained in his reply,as my c+p stated it wasn`t necessary in new construction,he was aghast at the ridiculousness of that particular situation and I happened to agree w/him on that point(hop,brokedown,darryl.florida ******* could all give you better answers to florida code if you want them:wink: )SHEESH !!!:laughing:


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## Big Bob (Jul 27, 2007)

FL legislature is lobbied heavy by new construction interests. New constuction does not require a Roofing Contractor... any GC ,GBC or RC can install roofing material on new constuction. code on new is basiclly per manufactures specs and nailing patterns per code ie. wind zone.

Re-roof code is driven by insurance carriers demanding stricter codes. Also higher rates and less exposure to risk.

SO FL homeowners pray for a claim so o&L coverage kicks in and the carrier foots all of the bill less deductible.


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## Ed the Roofer (Jan 27, 2007)

the roofing god said:


> SHEESH !!!:laughing:


I must be particularly oversensitive today after the call I got from the lady in my Good Day - Bad Day thread.

Now I understand the reason for the frequent caps.

Nothing personal, I just thought the question was appropriate for this thread content here, not for me to find out at your home base.

Ed


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## Docfletcher (Aug 1, 2007)

:thumbsup:




:laughing::laughing::laughing:


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## the roofing god (Aug 2, 2007)

apparently reading comprehension is no longer one of your strong suits ED,Thanks for the further explanation Big Bob,I kinda thought that was the deal when it said it wasn`t required for new construction,but didn`t really know who was from florida here.---Doc-what`s w/the thumbs up??et` tu brute` ??


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## Docfletcher (Aug 1, 2007)

You and Ed were quite succinct in elaborating your respective statements. I thought that the way the issue was put to bed was kinda cool. Martha would say "It's a good thing" . 

:laughing:


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## skymaster (Jun 6, 2007)

TRF; thanks for protecting what little shred of honor I have left:laughing: 
Doc, thanks to you also however one small note; your statement about putting something "to bed" OMG ya gonna get ED goin again:yes: :laughing: 
JackM


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## the roofing god (Aug 2, 2007)

hey skymaster,you live by my b-i-l he`s in mt.olive,anyway it`s TRG,TRF is what my wife calls me!:whistling2:


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## skymaster (Jun 6, 2007)

WELL, so much for that remnant of honor!!!!!!!!!:yes: 
X C UUUUUUUUUUUUUUUSE ME ROFLMAO
Mt Olive!!!!!!!! what a small world, b-i-l might be a neighbor!

SIR TRG:thumbup: :laughing: :yes: 
IF YA WANT AN EMAIL oooooppps damn caps fairy again :}
anyway if ya wants send me private msg and will give ya contact info. I can buy ya a coffacuppy by proxy thru your b-i-l :}:}:}:}:}
JackM


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## the roofing god (Aug 2, 2007)

thank you kind sir


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