How to Replace a Leaky Skylight | This Old House

How to Replace a Leaky Skylight | This Old House

all right now to get started here Paul what I want to do is I want to remove some shingles around the skylight and I want to start up high because the flashing runs up under the shingles how far out there got time well I'm going to go up about three or four courses all right so the first thing I need to do is I need to pull the nails all right now you see the nail right there yeah to get to that nail I have to go from down here get under the shingle bang it under the nail make sure it grabs it well push down gently pulling the shingle and the nail up at the same time now I simply bang down the shingle and pull out the nail you can make it look so easy okay with all of the shingles removed I see that the flashing that goes around the window starting at the bottom and the step flashing that goes up the sides looked like it was all done correctly starting at the bottom we then cover this first piece with a row of shingles and so on all the way up we need to remove the flashing so we can get at the window this top piece of flashing right here is called the counter flashing that seals the top edge of the step flashing okay now I want to pull this one up all I want to see where it's nailed okay get this removed may have to cut the membrane really stuck down all right now I got to cut the membrane there see we pull it out there it is there we go what are you doing that time I'm just going to cut the membrane away because I want to remove the membrane that runs up the side of the skylight to see if I can expose the brackets that hold the skylight to the roof we cut the membrane and then the skylight should pop right out all right Paul put your flat bar in the top corner of the window frame and push down on the roof and see if the window comes right out it comes right up that came out easy yeah roll it right down all right now I got to cut the membrane across the bottom okay now we can get it right up and out of the way all right here's our new skylight and there's a couple of things I wanted to do before we install it in the opening first I wanted to install the solar powered shade that you can open and close from down below there's a trim package that goes around the perimeter of the interior of the window and on the roof opening there's this vinyl strip that covers the edge of the drywall now on each side on this side here top other side and the bottom I mark Center lines those Center lines will reference off of the skylight that I put Center lines on the sides top and bottom also so now when we position this in the opening we'll line up our Center lines and the unit will be perfectly centered okay Paul how's it on that side you got to come up about an eighth of an inch okay me too looks good here okay good all right I think it's got to come this way a little bit that looks good perfect right there okay I'll nail it off so Tommy what kind of nails are you using these are a galvanized ring shank nail and they really bite into the wood now we're ready to flash the window to make it watertight so the first thing we did is we put a strip of the self sealing membrane along the bottom of the skylight now we're ready to install this metal flashing that the manufacturer supplies that will conform to the bottom so we're lifting up this gasket sliding the metal flashing under it dropping the gasket down and then I'll put a couple of small nails to hold it into place on the edge of the window right here now we're going to run some self sealing membrane up the side of the window over our first piece of flashing okay now I want the top edge to line up with the bottom edge of the window right there just push it right on I will peel off the paper keep it tight to the window yep okay it's good now we'll do the other side we're ready to install the first shingle slide it into position line it up we install our first jingle over our first piece of flashing now we're ready to step over that shingle with another piece of flashing I want to keep it up high so that you won't see it when I install my next shingle we're ready for the next shingle that will step on top of that flashing line it up you don't see the flashing but it's watertight so that's why they call it step flashing exactly now if you notice I put two nails on the edge of the shingle instead of one nail on this edge and one end on this I don't like to nail through the step flashing it's a chance for it to leak to cover this opening of the step flashing where it meets the window we're going to counter flash that and we're going to start at the bottom and work our way up and around the bottom on the side it's right into that little groove okay that's good all right now we'll just screw that together right here on the bottom okay now we got to do across the top okay one do you guys we're ready for our final piece of flashing and that will fit right over the top and under those shingles drop it down push down tight and we put a screw on each side a couple more shingles and we're all done well it's a good idea to put a drop cloth underneath this opening a lot of debris fell yeah that was great idea let's see if the solar-powered Shade where x-ball there it goes now all you have to do is paint up that trim and the windows all done


  • jose bonifacio says:

    Muito ótimo bom

  • Wild B says:

    Wow they did it in less than 7 minutes!

  • Tom Hardware says:

    The best way to fix a leaking skylight is to remove the old one and roof over the hole.

  • Michael Cardona says:

    Thank you soooo much

  • Erick Nava says:

    Is this considered a deck mounted or curb mounted skylight?

  • cengeb says:

    Before the new skylight replace the shingles, that roof is past its prime…cracked means old and done

  • Brian Henneman says:

    I have a roof leak (or maybe a skylight leak) next to a skylight that I can't seem to fix.  I've been up on the roof and in the attic a dozen times trying to fill every possible crack and nothing works.  Hope replacing the skylight will do the trick.

  • kirk58 says:

    On some shingles its impossible to seperate them to get a prybar underneath to remove the nails. The adhesive is baked on solid. You destroy the shingles in the process. This should have been mentioned in the video.

  • s ben says:

    No nails in the window frame. I just installed a Velux skylight and followed their installation steps. The nails go only on the side of the flashing never on the window. I guess contractors don't read instructions!

  • Rachel Moore says:


  • Skill Builder says:

    Terrible, fake, over-rated

  • Vance Fernandes says:

    Also at the bottom right corner where he started the shingles the flaps lined exactly over each other…poor practise…should stagger…

  • John S says:

    The new one could leak also. Notice that the last top flashing did not go under the shingles very far. Water will get under it through the shingle gaps.

  • Mike Nestle says:

    This is the best video on removing skylights anywhere. A lot of "This Old House" is not so easy to apply to structures in the Western USA but this is a pleasant exception.

  • Porsche924Tim says:

    It looked like the old skylight was installed properly… I wonder where it leaked???  We had to replace 2 Velux skylights that fogged up after 20 years, but never leaked.

  • Charles Damery says:

    Why not paint the trim before installing the skylight?

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