Guest User
6/9/2013
We have what is called a Jim Walter home. It is a frame home with the masonite siding on it. the house is roughly 56 ft long and 26 ft wide plus the hangover. Roughly 20 sq of shingles or 22.3 sq metal I have looked at lot of the questions and it raised several for me We have two layers of shingles on roof. It is 1/2 inch plywood supported by 2 x 6 rafters and double braced at each rafter We have half dozen different answers. We are not concerned with insurance company,city codes or selling problems Can we lay 1 x 4 treated lathe the length of the house and then add the metal to that with no problem ? Mfg says if we go directly onto shingles it will void their warranty .They did say we could do the lathe 1. should the lathe be 2 ft apart or further 2. will it ventilate correctly 3. should we insulate between the roof and the deck ? 4. Would the 1x 4 create a decent air space and be the insulation 5. would it be better and look better to tear the shingles off and and then put metal with a barrier on the roof 6. We have 3 bids at rougly 6500 that includes tearing shingles off and not tearing shingles off, we also have bids at 9600 up to 11 grand to tear and not tear shingles off . All of them are giving the same 30 year warranty and 5 or 10 warr on labor 7. Can I have someone climb on the roof after it is finished and put clear silicone over every screw for added protection What questions do we ask to be sure we get a good job and the best bang for the dollar. The wife retired Monday and I have just been awarded agent orange disability so we have to get this correct the first time around. I am no longer able to climb up and look and spot what will or will not work Any suggestions pitfalls and help would be greatly appreciated If the bids wee all in the same range I would just make a call but with the wide margin I am wondering why
Todd Miller
Isaiah Industries, Inc.
6/10/2013
Thanks for your post and thank you for considering metal. Many of your questions regarding installation need to be answered by the manufacturer of your roofing as the answer could vary from company to company. I have never before run into a metal roof manufacturer who voided warranty when going over the old roofing? What is their reasoning behind this? I would always suggest a layer of underlayment beneath the metal roof in all cases. Adding the horizontal boards creates a thermal break but does not help a lot with ventilation per se. The thermal break, however, does enhance energy efficiency. You may want to consider a roof that has reflective pigment in its coating for greater efficiency. Yes, you could seal over the screws but I am not sure it would really extend their life. I probably would not do it, not the first time around at least. You could also consider a metal roof that does not have exposed fasteners.
Guest User
6/10/2013
Thanks Todd for the reply and so fast. It seems you are here by yourself when it comes to replies lol My understanding is the heat build up and the second reason is the fasteners/screws may not be long enough to get a good hold in the decking under a double layer of shingles. I have talked to two mfgs. and both told me the same thing My biggest surprise is the vast difference in estimates I should have stated that all of them will install a ridge vent the length of the house and then vents under the eve of the house as well the 1 x 4 latheing are there any questions that are of real importance that I should ask before installing and is there any thing a person can watch to see if the install is correct Would you suggest tearingthe shingles off instead of leaveing them on
Todd Miller
Isaiah Industries, Inc.
6/10/2013
Thanks Doc. I don't quite understand the fastener situation because if they can fasten through the lathing into the decking, then they can fasten into the decking without the lathing. You can get screws like they use easily up to 3" in length. The lathing will act as a thermal break which will help keep from transferring as much heat from the roof into the attic. That is a good thing. Because the lathing runs horizontal, though, it will not provide active ventilation. Ventilating the ridge as exhaust and making sure you have good airflow into your attic from the soffits is wise. Really, I don';t feel you can go wrong any way you go. Leaving the old shingles on actually increases R Value of the roof assembly which is beneficial. Based upon all you're telling me, perhaps leave the shingles on, install underlayment, and the lathing ... and then a metal roof which meets Energy Star guidelines ... seems like that would be your best bet. It really comes down to what you want to pay for though. Every step, of course, involves cost.
Eric Novotny
An informed customer is the Best Customer!
6/10/2013
Doc, Can you attach a picture of the roof? I would like to know how the roof is vented, if at all, currently. What kind of color were you thinking of for the roof? In general, I would prefer to see the old layers removed and in the dump. This will keep the thermal mass off roof and the structure below much cooler. You can run an overdeck vent if your current roof is an insulated or hot roof design but if you have vented design and are going to put a light color on, there won't be nearly as much benefit.
Guest User
6/21/2013
Hello Todd, sorry for the delay I have been out of town The reason for the no warranty is if you do not put an underlayment the metal can be scratched by the shingle thus removing the protection with an underlayment they dont void it. I called back to get it clarified Right now the roof has two turbine vents on the back side there are vents on each gable end and then there are several under the eves along the roof line The lathes will run length wise of the house would you suggest they run up and down the roof instead ? You say running lengthwise that it will not provide active ventilation suggetions As to the roof vent we are considering using a ridge vent but we are concerned that it only comes in aplastic of some sort cant find a metal one again open to suggestions or is the plastic type good We are going with a lighter color like a tan not sure how well you can see this pic
Todd Miller
Isaiah Industries, Inc.
6/21/2013
My interpretation of the Int'l Building Code is that underlayment should be used even if the old shingles are left in place and even if battens are installed. The battens hat the roof fastens to must be run horizontally. You can cross batten with vertical battens first followed by horizontal and thus achieve an airspace which can be truly vented. It is possible to use a plastic ridge vent and then cap it with metal for protection. You may want to look at Cor A Vent and ProfileVent. You may want an Energy Star rated roof which would make you eligible for the 25(C) Federal Tax Credit up to $500.
Eric Novotny
An informed customer is the Best Customer!
6/23/2013
You need run the underlayment. If you have soffit vents, you could certainly get away with running a ridge vent and ditch the turbine/powered fans. If you have existing ventilation, I don't think there is a necessity for running the above deck venting. Go with a good roof color and solar reflective coating.
Guest User
6/26/2013
thanks for the replies, would have answered sooner but keep getting error that Iam spam Todd Iam not sure so would like to clarify the battens I would think I would run 1 x 4 up and down on the roof and then come back and lay 1 x 4 on top of them going long ways across the roof Is that correct We are laying an insulation which may be the same as the underlayment you are talking about if not the same then we will purcahse the underlayment and install it as well
Todd Miller
Isaiah Industries, Inc.
6/26/2013
Vertical followed by horizontal battens will be okay. Most insulations are not also an underlayment. I would suggest both.
Guest User
6/26/2013
will getthe underlayment and will install it along with the insulation We do appreciate the help and advice will send a pic when it is finished We have found a gem of a home repair man He is knowledgeable is way more than reasonable and does good work We are fortunate to run across the young man What has been answered on here is what he is saying so feel really good we have him doing the work for us Thanks for all the replies
Todd Miller
Isaiah Industries, Inc.
6/27/2013
Sounds good. Don't feel hesitant to ask more questions. Good luck!
Eric Novotny
An informed customer is the Best Customer!
6/27/2013
+1 Post pictures if you can. We love updates.

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