Upside down shingles

So basically I started reroofing my garage when I realized I was installing a typical 3 tab shingle upside down. Instead of the 3 tabs facing down they are facing up. Now, as far as I can figure this shouldn’t actually mess anything up as far as weatherproofing goes. After looking at the shingles it seems like the 3 tabs are merely cosmetic. The only problem I might be able to see is that the grooves between the three tabs are facing up instead of down, however, I have still installed the shingles such that there is 1 to 1.5 inches overlap and the tab grooves and nails are completely covered by the bottom (i.e. top) of the next overlying row of shingles.

So, I’ve only gotten 1/3 of one side of the garage done and I really don’t want to redo it I don’t have to. Although I will be installing the shingles here on out the correct way (yes, I know the will be a color difference) should I reinstall the ones I’ve done or can I treat them as a very long bottom strip of shingles and restart (allowing for the proper overlap concerning going the correct way now) from here on out? Basically, is there any reason beyond cosmetic reasons?

The top is what I’ve done, the bottom is how it’s supposed to be.


The keyways matter and are not just cosmetic. Water will run down the shingles and follow the path of least resistance (i.e. the keyways) and leak at your nails. You need to redo that area.


even though the keys are still completely covered (and the nails to) by the next layer?

edit pretend the red layer completely covers the green. I drew out the green just in case somebody needed a better visualization.

I would redo it because simply it wrong. Alot of things can come into play at this point. First of the top of my head is how will it hold itself down when the tar strip is in the wrong position. Odds are it will blow off rather easy. Second doing it correctly will make it more stable in wind and rain/snow situations. Read the back of the shingle bundle it will show you how to put the shingle on correctly.

I don’t even know where to start…
Did you read the package?
Wasn’t it a dead give away when it was so obviously different from the roof you were roofing over?
I find it very hard to believe that someone did something that dumb.
pics or shens…

While I agree, you should take it off and redo…if for no other reason than when someone sees it and says “What the f#ck happened there?” I don’t know about you, but there’s no way I’d want anyone to ever see that. It takes some big balls to admit that.

Having said that, I’ve watched a crew start roofing from the top of the building using three tabs, lifting to nail as they went down. I thought that was pretty funny.

-Axiom- stern but affective.

uh j ,
ill just call ya j ,
first, the top half of a three tab does is not as
strong as the bottom half. it looks the same but doesnt have as much fiberglass. so the to half will wear out in a couple a years if exsposed.

second, the water keys are very important.
run three tabs upside down and youll trap water
at the sides, where they but together.

third go to home depot, buy a 20 dollar tear off shovel with teeth and tear off upside downers, and
install rite side up.

dont forget you have a choice of color,
when laid correctly.



Can we get some pics for our sales folders? :mrgreen:

Sure! Anyhoo, obviously I’ve never laid shingles before. Yes I studied up on how to lay them. No I didn’t immediately start after studying up and quite frankly it’s a situation where I just started not even thinking “hey, is this the right way” and viola, here I am. Just looking at the shingle (after I realized the mistake - homer moment) I didn’t see any difference between the makeup of the material of the two sides and as you can see from the pictures it’s not as if it looks bad per se.

All I got to say is DAH !~!!!

IF you read the instructions that are on every package made on installation you would know that you are wrong. Strip it and start over. Glad to see you like to do things twice !! too bad you only get paid once.

Wow !! now ive seen it all .

a backwards roof ???

can someone say TEAR-OFF??

sorry jasbreus but this is just wrong .

Up to you what you want to do .

I know it is technically wrong. That’s why I asked my question in the first place. If, and only if, the performace would be the same would I consider keeping it as is. Yeah, it wouldn’t look nice (well unless I kept up the backwards installation) if I proceded to install the right way without stripping out the backwards installed stuff.

I realized what I did though. I started the starter strip correctly (I was planning on cutting off the tabs, it CAN be done like this though most just start off with the upside down shingle). Then (bright idea of course) “hey, we need to start installing the reverse of the starter strip.” hmmmm…uhhhh…whoops! :mrgreen:

This sucks that I have to rip it all out :frowning: (and yes, I know…place new felt down too)

Hey Jas we all make mistakes look at it on the bright side .

At least you didnt finish the whole roof :wink:

“This sucks that I have to rip it all out (and yes, I know…place new felt down too)”

I would tear it and start new but since everything is brand new I see no reason why you couldn’t go over the top.

I’ll just start over. “If you’re going to do it, do it right.”

Aahhhh…life’s little lessons…yes I am VERY glad I didn’t have the whole roof done!!!

If it makes you feel better you can use some of those shingles as starter and ridge caps . as long as the removal damage is minimal and you repair it with roof cement :wink:

it looks like you have a 5 in overhang on your first row of shingles. it should only be 3/8 in.

believe it or not…i have seen much worse…ther is a garage in my town that i saw from a roof top last year that is 100% upside down. you just have upside down shingles. this one was upside down shingles started at the top…hence designed to catch water at every shingle…and worst yet…all the shingles are perfectly lined up straight up the roof ( no steps) i should try to sneak in the yard and get a pic.

he already said that is the starter course without the tabs cut off yet.