Roofing Tar for window corners

[wanderingturtl]

Someone talk me out of using roofing tar for lower window corners.

 

[AlphaHare]

Um, just don't. There are a ton of options better than roofing tar IMO.

Use butyl rubber instead, or one of the many industrial weather-stripping tapes (I like the ZIP system tapes at HD and Lowes), or both.

Tar will probably seal for a bit, but it will also get warm, run, and drip.

Caulking sealant
https://www.amazon.com/gp/product/B003VARIII

Butyl strip (very sticky both sides - used for RV window installs and other)
https://www.amazon.com/Butyl-Black-Thick-Rubber-Sealant/dp/B07PW3W33M/

Butyl tape (sticky one side)
https://www.amazon.com/dp/B0CQF65YS5/?th=1

 

[1dmpo]

Don't do it

It's gonna run as it weathers and look nasty on a nice pain job.

 

[kidharris]

Someone talk me out of using roofing tar for lower window corners.

What do you mean by the word "tar"? Tar is a generic term that is usually used to refer to bitumen, aka asphalt, or coal tar pitch, which is very brittle when solid. Both are hydrocarbons and will burn or melt at lower temps. I believe you actually are refering to plastic roofing cement which is asphalt + various additives mixed with a solvent and possibly fibers, to help prevent cracking and doesn't require heat to apply.


Reasons for not using it are.... it sucks to work with, is very difficult to seal metal with because metal expands and shrinks with temp changes much differently than the plastic cement which is not very flexible, doesn't play well with paint or caulks, cracks, and is a pain to remove. You need some type of flexible caulk to deal with aluminums high thermal coefficient of expansion. It helps if the caulk is paintable to conceal flaws

 

[LargeMarge-TC]

Instead of roofing tar on my windows, I think I would go with tin-foil.
Or rattle-can them.
Your choice of colors!

 

[hmoore]

What do you mean by the word "tar"? Tar is a generic term that is usually used to refer to bitumen, aka asphalt, or coal tar pitch, which is very brittle when solid. Both are hydrocarbons and will burn or melt at lower temps. I believe you actually are refering to plastic roofing cement which is asphalt + various additives mixed with a solvent and possibly fibers, to help prevent cracking and doesn't require heat to apply.

Reasons for not using it are... it sucks to work with, is very difficult to seal metal with because metal expands and shrinks with temp changes much differently than the plastic cement which is not very flexible, doesn't play well with paint or caulks, cracks, and is a pain to remove. You need some type of flexible caulk to deal with aluminum's high thermal coefficient of expansion. It helps if the caulk is paintable to conceal flaws, as many chicago il roofers would tell you.

I tried to use roofing tar for window corners, and really work with it is inconvenient. When the temperature changes, the material quickly cracks or falls off, and if something needs to be fixed or repainted, tar holds poorly under paint and it is difficult to remove. In my opinion, for such tasks it is better to use more elastic and flexible sealants that do not become brittle over time and are easier to disguise.