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monorris
Replacing and EPDM Roof
monorris

I own a condo in an old Boston brownstone. The flat roof on the building consist of an old asphalt and gravel roof covered with fiberboard and EPDM. After several years of patching it is time to replace the EPDM layer of the roof (multiple roofers have told us this was coming over the years). We have two contractors we are looking at for the job.

Contractor #1 - Recommends not removing the current EPDM layer and fiberboard. He would instal a layer of insulation and fiber board over the current EPDM and a new EPDM layer.
Contractor #2 - Recommends removing the current layers of EPDM and fiberboard and install a new layer of Readyboard and a new EPDM layer.

Obviously the quote from contractor #1 is much less expensive.

Does the old layer of EPDM and fiberboard need to be removed?

Is fiberboard still an acceptable layer under EPDM versus using Readyboard? (contractor #2 feels that if moisture gets onto fiber board it breaks down and this has accelerate the decline in the roof.

A. Spruce
Re: Replacing and EPDM Roof
A. Spruce

Either method will work, but here's the thing, if you add layers upon layers, you have a weaker roof that is prone to more problems. If you strip the roof to a bare deck and start anew, you will get a roof that will last longer and will have removed all the issues of the old roof.

Money saved now gets spent later in the way of needless repairs and premature failure/replacement. Money spent now, saves the headaches, hassles, and costs of problems in the future.

ed21
Re: Replacing and EPDM Roof
ed21

I pretty much agree to remove all old with new. Be sure enough insulation is added as well as all flashing, terminations, penetrations are replaced. This may include gutters or roof drains. If the slope of the roof needs help, now is the time to add sloped insulation.

dj1
Re: Replacing and EPDM Roof
dj1

Go with option 2, as mentioned, you have to remove the old roofing materials off. Repair everything that looks bad and re-do it from scratch. I won't do it any other way, and so should you.

llmotoll
Re: Replacing and EPDM Roof
llmotoll

Readyboard? is this slang or a nickname for a wood fiber board or a fanfold EPS insulation?

code will not allow 3 layers of roofing installed in most localities.

Leaving the bottom layer of built up roofing will provide a grandfathered fire rating to your roof system according to code, however it can hide deteriorated wood decking. Take steps to verify any bad deck is replaced during the roof renovation.
Contractor #1 may have a unit price in his bid to replace any existing wet insulation, if so by the time he is finished you could end up spending more than the 2nd contractor.
Contractor #2 recommendation would be the industry standard. Regardless of the insulation type used. However standard 1/2" polyisocyanurate commonly referred to as "iso" insulation is the same price as wood fiber board and does not absorb water as easily and it is far less weight per square foot.
Being in the north keep in mind additional layers of roofing will rob you of collateral weight load. Any time you get a chance to reduce the weight load on a flat roof you should leap at the opportunity. There exceptions to that, but not on a residential dwelling.

Recommend at least a .060 mil thickness while you are at it. You gain approximately 7 lbs per square inch puncture resistance. Greater puncture resistance can be gained using a more dense insulation

Another roof system assembly rising in popularity in our area of the world here in VA is to remove all roofing to the deck and install XR112 white TPO fleece backed membrane either mechanically fastened or fully adhered directly to the wood deck with No insulation. As most residential dwellings already have insulation in the attic or above the interior ceiling. Most of the expense in a flat roof assembly is the shipping, cost, handling of the insulation. To eliminate it entirely will in most cases allow big savings even though you will spend bit more on a heavier membrane roof system. The TPO or PVC are hot air welded together. So there is no worries on decay of field seams and if the roof has a tendency to pond water the thermoplastic membrane is the best system.

llmotoll
Re: Replacing and EPDM Roof
llmotoll
monorris wrote:

Is fiberboard still an acceptable layer under EPDM versus using Readyboard? (contractor #2 feels that if moisture gets onto fiber board it breaks down and this has accelerate the decline in the roof.

Never heard of Readyboard. Not able to find an SDS sheet for it on Google. Could be a nickname. At any rate he is correct about the consequences of moisture on wood fiber board. It is not good. when WF gets wet its initial response is to swell a bit and then eventually air from the non monolithic deck (the existing BUR system left in place will slow air filtration) will allow the insulation to dry out. When dry the WF looses its density and shrinks. This will make any screws that were used to hold the insulation or membrane roof in place appear to have backed out and poke up into the membrane. compromising attachment and a trip hazard or you would ever need to shovel snow off the roof you stand a greater chance of getting a puncture at each poking screw head.
Over the course of the intended service life of an EPDM roof system being 25-35 yrs with routine maintenance. Unfortunately your likely to spring a leak somewhere in that time frame and the wood fiber board will be damaged. best to cut it out and replace it each time you have a leak rather than let it go and face premature roof replacement a year or two later.

llmotoll
Re: Replacing and EPDM Roof
llmotoll
monorris wrote:

Contractor #2 - install a new layer of Readyboard

Is fiberboard still an acceptable layer under EPDM versus using Readyboard? (contractor #2 feels that if moisture gets onto fiber board it breaks down and this has accelerate the decline in the roof.

Found it!! Yes Readyboard is a great insulation. Far superior to wood fiber board. Yes! absolutely would recommend this brand over WF

monorris
Re: Replacing and EPDM Roof
monorris

Thanks for the help! This is what I was thinking, but getting some additional opinions always helps.

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