Home & Garden

Exterior Window Caulking

  • Last Updated:
  • Mar 27th, 2020 1:16 am
[OP]
Jr. Member
Jun 23, 2019
149 posts
50 upvotes

Exterior Window Caulking

Hey everyone, what kind of caulking do the builders use on new construction houses to caulk the exterior windows? I noticed the caulking has a very matte/rough finish compared to silicone which is usually has a very glossy finish. I need to re-caulk some areas and I want it to blend in with the existing caulking. When I had my A/C installed they used silicone around the line set entry point to the house and its very glossy and stands out, so I wanna make sure I get the correct stuff.
26 replies
Deal Addict
User avatar
Dec 12, 2006
4307 posts
523 upvotes
Messed Up Area
Use thermoplastic sealant.
Member
Jan 7, 2013
442 posts
197 upvotes
Oshawa, Ontario
Mulco makes good exterior sealant. Supra I think. Not quite as glossy as silicone but doesnt dirty up as much as the common DIY caulking. You could get it at Rona, if they are still around.
Deal Addict
Nov 9, 2008
1396 posts
435 upvotes
Toronto
+1 Mulco. I think they sell Mulco Flextra @ Rona.

Hardware stores are considered essential so should stay open i think?
Newbie
Feb 26, 2019
87 posts
58 upvotes
Mulco is excellent stuff. The consumer version available at big box stores is called Flextra. The good stuff is called Supra Expert. It’s even better, but full of VOCs, and allegedly only sold to “licensed contractors”. Just pop into a roof mart or builder supply yard and they will sell you some, cash and carry. It seriously smells, make sure it’s not exposed to your interior at all.
[OP]
Jr. Member
Jun 23, 2019
149 posts
50 upvotes
Is Mulco what the builder originally used? My main concern is the caulking matching the existing caulking. I need to fill some areas where the existing caulking shrunk so it has to match what I currently have.
Deal Addict
User avatar
Jun 12, 2008
2542 posts
398 upvotes
Ancaster
Another vote for Mulco Supra Expert. It looks glossy going on but fades to satin/flat within a few months.

A trick I have for tooling it is that you get some warm water with a couple of drops of dish liquid mixed in. It really helps to dip your finger into the water before tooling the caulking.
Last edited by nielboy on Mar 25th, 2020 9:08 am, edited 1 time in total.
Deal Addict
May 18, 2015
1428 posts
433 upvotes
Ottawa,Ont
vrscdx wrote: Is Mulco what the builder originally used? My main concern is the caulking matching the existing caulking. I need to fill some areas where the existing caulking shrunk so it has to match what I currently have.
no one can answer this without seeing it. And even with seeing it could only offer a best guess
Member
Dec 31, 2007
417 posts
105 upvotes
vrscdx wrote: Hey everyone, what kind of caulking do the builders use on new construction houses to caulk the exterior windows? I noticed the caulking has a very matte/rough finish compared to silicone which is usually has a very glossy finish. I need to re-caulk some areas and I want it to blend in with the existing caulking. When I had my A/C installed they used silicone around the line set entry point to the house and its very glossy and stands out, so I wanna make sure I get the correct stuff.
i'm pretty sure the use poly-urethane sealant. my brother's house and my house seem to be caulked with the similar sealant. this stuff seems to harden and dries out to the point that after 14 years it becomes shrunken, cracked and brittle and there are significant shrink gaps. my house is only 9 years ols and when i compared the two, they look quite similar

i'm pretty sure i found what the builders used.

https://www.tremcosealants.com/fileshar ... 0FC_DS.pdf

i've been using dowsil for caulking the exterior now. it's pretty good stuff, but it a silicon sealant and difficult to tool nicely to get a good finish. it takes practice to tool it nicely. i bought it from c2s, cause you can't buy dowsil from HD,, rona or lowes.

https://cs2sales.com/

it's cheaper buy the carton and much better than GE, mono or DAP. i like it better cause it's not glossy, like DAP or GE, it leaves a really nice matte finish.

my major project this year is to re-caulk my entire exterior windows and door with dowsil. there's a number of different formulations. i can't recall which one it got, but it pretty damned good stuff. it's silicone and remain pliable and shrink proof. i'll need to scrape every bit of the old polyurethane caulking off. my advice is to tape off the window and masonry, so you don't spread it where you dont want it to go. i found that silicone caulking is difficult to tool at best. practice tooling the caulking finish in order to get your technique down. it'll probably take me weeks to do the entire exterior. i thought about getting an electric caulking gun but there was no point as it was fairly easily to squeeze out. the tooling was what took the most time. also i found it was best to tool sections at a time, and also rip off the tape before the silicone starts to skin up and cure cause otherwise it will leave marks and the tooling finish will be ruined.

tooling silicone sealant really does require some skill and artistry. i'm not the best but my results looks better than what the original builder contractor did.

and since it is silicone, it's not paintable, so make sure you refinish your sills first or at least clean the surface in order to get a good finish and a clean look.
Newbie
Feb 26, 2019
87 posts
58 upvotes
Maybe a member who knows better can comment, but I thought you weren’t supposed to tool exterior caulking the same way you were with caulking like in your bathroom.

I thought you were supposed to leave it beaded up, rather than wipe up the excess and leave a concave surface.
Last edited by dottawat on Mar 25th, 2020 4:13 pm, edited 1 time in total.
Deal Fanatic
Jan 25, 2007
7611 posts
3668 upvotes
Paris
vrscdx wrote: Is Mulco what the builder originally used? My main concern is the caulking matching the existing caulking. I need to fill some areas where the existing caulking shrunk so it has to match what I currently have.
Zero chance the builder used a premium sealant. They used cheap stuff, which is why you are now having to deal with this issue.
For sale: Ego 56V 5aH batteries, BNIB
https://forums.redflagdeals.com/ego-law ... h-2294293/
Sr. Member
Feb 11, 2018
626 posts
592 upvotes
vrscdx wrote: Hey everyone, what kind of caulking do the builders use on new construction houses to caulk the exterior windows? I noticed the caulking has a very matte/rough finish compared to silicone which is usually has a very glossy finish. I need to re-caulk some areas and I want it to blend in with the existing caulking. When I had my A/C installed they used silicone around the line set entry point to the house and its very glossy and stands out, so I wanna make sure I get the correct stuff.
Get the Dymonic FC or 100. Used by some (higher quality) builders. You won't find it at big box stores or Rona...

See here...
Images
  • 100_1640.JPG
There are two types of people on this planet: those who react to events and those who anticipate them.

Pride is man's descent into hell.
[OP]
Jr. Member
Jun 23, 2019
149 posts
50 upvotes
Thanks everyone for the replies, I'll look into Mulco. The house is less that 2 years old, but the builder says the caulking is only covered for a year. It's only two windows in the master bedroom that have this issue, so perhaps they were the last two that gone done that day and they rushed it.

Top