Testing Drip Edge Installations on Roofing | Ask This Old House

[Music] tell me you got the roof out huh I sure do I want to show you a demonstration on how water can come off the roof and right the underside of your roof I know that you are a stickler for keeping the house dry because you've seen the damage water can do oh it's amazing and it can attack off your face your board your side walls and even hundred and eath the roof shingles let me show you right here I've got a perfect example of a shed yeah alright and on the leading edge of the shed there is a no drip edge but if you take a close look at the sheathing underneath the shingle you can see how the sheathing is black the structure is black and the sidewall eventually is going to get black so you can tell it's wet even though the shingles overhang the sheathing and the edge there right once the roof gets wet the water comes down over the edge and gets sucked into the sheathing and it will come right up the wall and eventually rot all of this this has got to be back four or five inches to rot right there I mean it's sort of inconceivable to think of the water will run uphill that works on surface tension let me show you I've set up a little demonstration here so surface tension is being what that the water will actually stick to surfaces yep it'll stick to the surface and it'll roll over the edge of the surface and then get drawn back up all right okay you've got a prop what's I got a prop here I've got three different props this is the first one this is similar to what we see over there and the picture that I showed you so we've got the shingles close to the edge of the sheathing and receding with no drip edge the water's gonna come down I have to wait just a little bit there it is see it oh wow that didn't take long at all huh see you know it's getting drawn right under the sheathing so it's getting pulled right to the sheathing yeah it's also getting pulled literally backwards and then running down the face of the fascia right the wetter the wood gets the higher the waters gonna go okay so now if you put on a metal drip edge you know now this is a metal drip edge right here now there's different sizes and different with this is just a standard 8 inch drip edge and you see that little band on the bottom right here and I do that's a kicker and that's so that if water comes off the edge and get sucked back in the water droplets will fall away from the face you so if we put this over this scenario right here which is what you've got on a second prop right it should work it will work a little better but it's not gonna work right oh man it's wrapping itself in hitting the drip edge it's still wetting the fascia board I mean there's still a lot of water just running down the fascia yep now because the overhang isn't far enough out yeah it's gonna shorten the life of the fascia boy so the drip edge is definitely doing something but it's not that effective so let's see what it does on the third one okay so now on the third one I've taken the the drip edge and I've created a gap the thickness of my finger I've also overhung the shingles 3/8 to 1/2 an inch which is more than in the second example right so right off the bat shingles are overhanging so much it doesn't even pull it back to the drip edge much right it won't drop if it does get blown in there from wind but it's really not gonna be surface tension should start to stick but it will fall off nothing on the fascia nothing on the fascia board because we're out and it's very important that the leading edge of the roof is an inch and a half to an inch and 3/4 away from the fascia board so same materials of the second example but way more effective just because they're installed properly absolutely and that's a good way to keep your fascia board dry and the underside of your roof dry and you know what this application is the same whether you run up the rake boards nice good info Tommy thank you my pleasure thanks for watching this whole house has got a video for just about every home improvement project so be sure to check out the others and if you'd like we can see click on the subscribe button make sure that you get our newest videos writing your feed

Channel: This Old House

Views: 206,769

Rating: 4.9215965 out of 5

Keywords: tom silva, kevin o'connor, roofing, gutter, drainage, drip edge, 4-6 minutes, This Old House, Ask This Old House, DIY, Home Improvement, DIY Ideas, Renovation, Renovation Ideas, How To Fix, How To Install, How To Build, Kevin o’connor, kevin o'connor house, kevin o'connor this old house, kevin o'connor ask this old house, kevin o'connor interview, tom silva this old house, tom silva house, tom silva construction, tom silva tools, tommy silva

Id: sDTCTbyyg1s

Length: 4min 6sec (246 seconds)

Published: Fri Jan 11 2019