Replies

1. 
   BarryE | Oct 31, 2007 01:28am | #1

   http://forums.taunton.com/tp-breaktime/messages?msg=96209.1

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   Barry E-Remodeler

    

2. 
   DanH | Oct 31, 2007 03:39am | #2

   The main problem is that good caulk, like good tools and good appliances, lasts so long that even if you can remember what it was you can no longer find the same stuff when it comes time to replace it.

   If your view never changes you're following the wrong leader
3. 
   WINSTALL | Oct 31, 2007 02:59pm | #3

   np-1, or Sika-flex. I use nothing but urethane based caulk. I love it. It holds up well and paints well. Bridges large areas and tools very smooth.

4. 
   Crawdad | Oct 31, 2007 03:34pm | #4

   thanks to all

5. 
   csnow | Oct 31, 2007 06:47pm | #5

   I think it depends a lot on the application.

   For example, polyurethane caulks are unbelievable performers, but are expensive and difficult to tool.  It's worth asking- Is this a critical joint, or just for appearance?  Exposed to extremes or well protected? 

   Also, prep and technique are big factors no matter what you are using. 

   For example, the instructions for the Pella windows I just installed specificied a 3/8 gap between the trim, use of backer rod, and poly caulk.  Also it specified that the trim should be pre-primed caulk edge  That was surprisingly thorough advice.

   The backer rod ensures that the bead is not too deep, allowing more stretch.  The 3/8 gap ensure that the bead is wide enough to support stretch from expansion/contraction.  The primer ensures a good bond.

1. 
   Crawdad | Nov 01, 2007 12:38am | #6

   Critical joint, between azek trim and Andersen window.   I have read about caulk backer jount material numerous times but haven'seen it anywhere.  Where in the heck do you get the stuff?

1. 
   Gene_Davis | Nov 01, 2007 01:28am | #7

   My recommendation for your app is OSI Quad, which is available in colors that match most all of the Hardy factory paints.

   View Image

1. 
   DaveRicheson | Nov 06, 2007 07:11am | #16

   I don't know how Quad performes on Hardi, but on steel siding in direct sunlight it only lasted about 4 years for me. On the full shade side it has gone over 6 years so far. I have also used it at work on an alum. flashing and EIFS joint. Same story, southern direct sunlight exposures are failing.

   I use to be a big fan of OSI Quad, but experience is changing my mind.

    

   Dave

2. 
   BillHartmann | Nov 01, 2007 04:41am | #10

   Every home horror store and hardware store that I have been in has backerrod.But for some strange reason it is by the weather stripping and not the caulks..
   .
   A-holes. Hey every group has to have one. And I have been elected to be the one. I should make that my tagline.

1. 
   DonCanDo | Nov 01, 2007 12:32pm | #12

   I've got to take a better look, but I have NEVER seen backer rod at the big box and the one time I asked for it at a lumber yard, they didn't know what I was talking about.  I always just assumed that using backer rod was one of those really good ideas that nobody actually ever did.

1. 
   Crawdad | Nov 01, 2007 04:25pm | #14

   LOL kinda what I figured too-  thanks to all who replied with info

2. 
   BryanSayer | Nov 06, 2007 07:28pm | #18

   If they don't know what you are talking about when you say "foam backer rod" ask for "caulk saver".Places that specialize in waterproofing materials may sell it by the foot and have more choices as to diameters.

2. 
   Crawdad | Nov 01, 2007 04:20pm | #13

   Aha, by the weatherstripping.  I'll try that today.

6. 
   ted | Nov 01, 2007 03:22am | #8

   my first choice is polyurethane. 2nd is some commercial stuff called Tremco Mono which is essentially a butyl rubber type sealant that has some proprietary ingredients that make it easier to tool. I use silicone on rare occasions.

7. 
   Jeff_Clarke | Nov 01, 2007 04:36am | #9

   http://www.npcsealants.com/900.htm

    

   Jeff

8. 
   Dinosaur | Nov 01, 2007 05:52am | #11

   View Imagehttp://mulco.ca/En/Industriel/produits/Produits_c_ext.htm

    

   SUPRA is an industrial-grade thermoplastic sealant. It's unbelievably smooth to work with; if you have a good hand with your caulking gun, you won't have to tool it at all. The cartridges are certified bubble free, and it comes in about 50 colours. The stuff lasts over 20 years without degrading in stretch or adhesion, and does not harden or require chipping or scraping to remove even after many years in an exterior application. Generally only available at trade suppliers, not big boxes or hardware stores.

   The consumer version of this product is called FLEXTRA, and is available in most big-box stores. It works and performs much like Supra but isn't available in as many colours, and I don't remember if the cartridges are certified to be bubble-free.

   Either of these products will change the way you think about caulking forever. I will no longer willingly use any other product except for specialty applications such as chimney flashings (high-heat silicone) or screw-down steel roof (butyl).

   Dinosaur

   How now, Mighty Sauron, that thou art not brought
   low by this? For thine evil pales before that which
   foolish men call Justice....
   

   

9. 
   rogue | Nov 06, 2007 06:34am | #15

   As far as the backer you're referring to, we call it rod-stock around here in. If your hardware store doesn't have look for someplace that has brick supplies, 'cuz they have to have it for their expansion joints.

   As far as the best caulk for all around exterior use, I wouldn't consider anything but pro geocel. It goes on well, and neat in hot or cold and I've pulled stuff off that was over ten years old that was still flexible and no signs of wear.

10. 
    Toolpig | Nov 06, 2007 02:57pm | #17

    Been using DAP "Sidewinder" for fiber-cement siding.  Best I've ever used!  Cleans up easy, paintable and stays flexible (basically turns to rubber when cured).  Much better than latex IMHO.  Tube says you can apply it in "sub-zero" temps, which is important here in the northeast.

    Geocel 2300 is another good bet, especially for roofing applications.

    TP

     

    Toolpig (a.k.a. The man formerly known as "Toolfreak" and "Toolfanatic")
11. 
    blackdiamondcaulking | Mar 05, 2025 11:54pm | #19

    For exterior window installations, silicone or polyurethane caulk are your best bets for durability and weather resistance. Here’s a quick breakdown of the options:

    100% Silicone – Excellent for waterproofing, flexibility, and longevity. It won’t shrink or crack but isn’t paintable.
    Paintable Silicone – A hybrid option that combines the durability of silicone with the ability to be painted. Good if you want to match trim color.
    Polyurethane (PU) Caulk – Extremely strong, flexible, and weather-resistant. It adheres well to various surfaces but can be harder to work with.
    Acrylic Latex – Easy to apply and paintable but doesn’t hold up as long in extreme conditions compared to silicone or PU.
    For long-term durability, I’d recommend GE Silicone II, OSI Quad Max (polyurethane), or DAP Dynaflex 230 (paintable hybrid). If your area experiences harsh weather, silicone or polyurethane will last the longest.

    What’s your climate like? That might help narrow down the best choice.

    For more you also visit https://blackdiamondcaulking.com.au/