Almost every construction professional and DIYer is familiar with DAP products. Their Alex Caulk is one of the most popular brands of sealant sold in big box stores nationwide. We also review DAP DynaGrip Construction Adhesive, a premium product for flooring and similar uses. This product actually won a Pro Tool Innovation Award in 2017. They even made a "superglue" called DAP Rapidfuse. DAP DynaFlex Ultra is an exterior sealant designed for use on windows, doors and even vinyl siding joints. It is particularly good at handling the intersection of HardiBoard and tracery. A key property of a window and door sealant is that it remains flexible throughout, so it can adapt to weather changes that cause other sealants to crack or crack.
DAP says the DynaFlex Ultra uses Weather Max technology. It's a trade name because of its UV protection, flexibility, and stain resistance, making it a solid product for handling anything from harsh sun exposure to extreme cold and rain. Especially UV resistance to prevent fading, yellowing, cracking, chalking and chipping.
DAP has done a great job of spreading the word about the benefits of DynaFlex. Once cured, DAP DynaFlex Ultra resists mold, mildew and algae throughout the life of the sealer. It creates a permanent watertight seal that stays in place during the expected contraction and expansion of the building material throughout the season. DAP DynaFlex Ultra can be exposed to rain and can be painted within one hour of application.
After inserting the tube and cutting a 1/4" hole in the nozzle, I immediately noticed that the sealant flowed immediately. There are no foil seals inside the tube to pierce, and DynaFlex flows more easily than traditional caulks. It also stops when you exit the applicator. Not all of us run with the Milwaukee M18 Cordless Caulking Gun, so ease of use is important.
The gaps around our office doors and vinyl trim became the first use for DynaFlex. It goes on easily and I like how the sealant flows. It's easier to insert than traditional Alex caulk or even 230, yet still manageable. I never felt the flow was gone from me – unless I forgot to withdraw the applicator.
DAP DynaFlex Ultra sealant also helped a 1920's bungalow that had been redone with HardiBoard siding. While the siding looks great and the remodeled home is in good condition, most of the window trim needs patching. In many places, the original caulk had shrunk, cracked and/or split. Taking the time to reapply new DynaFlex sealer in these areas in preparation for repainting becomes an easy priority.
Of course, summer in Central Florida means rain—a lot. The two-hour window of DAP DynaFlex Ultra Window and Door Sealant allowed us to find breaks in the rain and get the job done quickly. In some cases, it rained more than an hour after application. Looking back at the work, this doesn't seem to have affected the work.
DAP DynaFlex Ultra and DynaFlex 230
When comparing the DAP DynaFlex Ultra to the DynaFlex 230, a few key things came to light. For one, the DynaFlex Ultra is more flexible and has a mobility rating of 35 (except for clear), while the DynaFlex 230 has a rating of 25. DynaFlex Ultra was just more flexible – and still is. It also has very good resistance to UV yellowing. The same resistance gives it longer resilience against hardening, cracking or splitting. The DAP DynaFlex 230 is currently available in a wider range of colors than the Ultra, but it has been on the market longer. It also fills a larger void. Both products are latex-based and clean up easily with water.
Other differences and comparative specs:
| DynaFlex Ultra | DynaFlex 230 | |
| dynamic joint movement | +/- 35% (ASTM C920 Grade 35) | +/- 25% (ASTM C920 Grade 25) |
| Maximum Connector Size | 3/8″ – 1/2″ | 1" |
| drawing time | 1 hour (clear 2 hours) | 2-4 hours |
in conclusion
When you're talking window and door sealants, you need to choose wisely. Choosing the wrong product can cost you in the long run. You always have to go back and reseal door trims, window frames or other areas. The price of DAP is about $6.28/tube or $75.36/case. Its most common colors are white and beige, but you can also order it in clear, clay, dark bronze and iron gray.
Because it stays permanently pliable (we checked after a few weeks), this product makes perfect sense for filling gaps up to 3/8 inch. I wish I had used it on previous products as it would have saved me a lot of time. The price and ease of use make it an easy recommendation, and we think DAP offers a product that delivers great performance. If "architectural grade" is what you want, the DynaFlex 230 is the product for you. For even better UV and weather protection, the DAP DynaFlex Ultra seems to deliver.
You can find out more about DAP DynaFlex Ultra here.