AU-1 is a water-based sealant from Tower Sealants. It cleans up with soap and water. It has no plasticizers, so it will not bleed through your paint. It has also been tested with Benjamin Moore paint systems. From Nov. 9 to 13, you can see it for yourself at our five stores.
Paint is only as good as what is under it. A cheap caulk can crack, pull away or stain the paint over it. Then the whole job looks bad, even when the paint is great. That is why we want you to know what goes into the joint before the brush comes out.
Don’t chance your quality coatings with an inferior sealant.
Meet the professional team from Tower Sealants and The Color House. Watch AU-1 go on real joints, test it yourself and see how it compares to other brands. Every stop runs 7 to 10 am. All are welcome.
What is AU-1 sealant?
AU-1 is a commercial construction sealant made by Tower Sealants. It uses acrylic urethane. Tower built it to beat polyurethanes, hybrids and silicones on waterproofing jobs and window installs.
- Water-based, so it cleans up with soap and water
- No plasticizers, so no loss of flexibility and no shiners
- A strong UV inhibitor package to stand up to the sun
- Meets ASTM C-920 Class 35
- Comes in cartridges, sausages and pails
There is also AU-1 Hybrid for wet and cold days.
AU-1 vs. the competition
Here is how AU-1 stacks up against four sealants many pros already use. Look at the cleanup row first. Every other brand needs a solvent. AU-1 needs soap and water.
| AU-1 | Sika Flex 1-A | BASF NP-1 | Tremco Dymonic 100 | Pecora Dynatrol I-XL | |
|---|---|---|---|---|---|
| Cleanup | Soap and water | Sika Remover-208 | Xylene | Xylene | Mineral spirits |
| Low VOC, solvent free | ✓ | ✕ | ✕ | ✕ | ✕ |
| No mold or mildew from plasticizers | ✓ | ✕ | ✕ | ✕ | ✕ |
| No paint discoloration or shiners | ✓ | ✕ | ✕ | ✕ | ✕ |
| No primer on most surfaces | ✓ | ✕ | ✓ | ✓ | ✕ |
| Strike flat, no extra tooling | ✓ | ✕ | ✕ | ✕ | ✕ |
| Resealable and reusable | ✓ | ✕ | ✕ | ✕ | ✕ |
| Shelf life | 2 years | 6 to 12 mo | 12 mo | 12 mo | 12 mo |
| Maximum joint width | 2″ | 1.5″ | 1.5″ | 1″ | 1″ |
✓ yes · ✕ no. Source: Tower Sealants AU-1 competitive comparison sheet, based on Tower’s internal testing.
Why soap and water cleanup matters
Most pro sealants need xylene, mineral spirits or a special remover to clean up. Those are harsh. They smell. You have to buy them, store them and get rid of them. With AU-1, you wipe your tools and hands with soap and water. That is it.
Why no plasticizers matters
Many sealants use plasticizers to stay soft. Over time, those plasticizers can move out of the caulk and into your paint. That can leave shiny or sticky spots called shiners. It can also feed mold and mildew. The caulk itself gets stiff and can crack.
AU-1 has no plasticizers. So the paint over it stays clean, and the joint stays flexible.
Tested with Benjamin Moore paint
We sell Benjamin Moore, so we care about what goes under it. Tower has tested AU-1 for compatibility with Benjamin Moore paint systems. You can see the results in Tower’s compatibility guide.
Meet AU-1 LAB, the air and water barrier
AU-1 LAB is part of the AU-1 family. LAB stands for liquid-applied barrier. It is one product that does two jobs.
Air and water barrier
Coat the whole wall to make one seamless layer that keeps air and water out of the building.
Liquid flashing
Apply it around rough openings for windows and doors to stop wind-driven rain.
Here is what AU-1 LAB brings to the job:
- Brush it, roll it or spray it
- Soap and water cleanup
- No primer needed
- Sticks well, even to green concrete
- Seals itself around fasteners, even after it cures
- Works with stucco, EIFS and most common cladding systems
- Weather and tear resistant
- Meets the performance requirements of AAMA 714-22 and is tested to ABAA requirements for weather-resistive barrier materials
- Comes in 1 gallon and 5 gallon pails
AU-1 LAB vs. other barriers
Tower compared AU-1 LAB to six well-known barriers and to regular house wrap. Here are some of the biggest differences.
| AU-1 LAB | Henry Air-Bloc All Weather STPE | Prosoco R-Guard Spray Wrap MVP | Tremco ExoAir 230 | DOW Defendair 200C | Sika SikaGuard AWB 660 | PolyGuard BB LW | House wrap | |
|---|---|---|---|---|---|---|---|---|
| 2-in-1 barrier and liquid flashing | ✓ | ✕ | ✕ | ✕ | ✕ | ✕ | ✕ | ✕ |
| No prep on joints under 1/4″ | ✓ | ✕ | ✕ | ✕ | ✕ | ✕ | ✕ | ✕ |
| Air permeance (lower is better) | 0.0008 | 0.0050 | 0.0024 | 0.013 | 0.0117 | 0.0049 | Not listed | 0.004 to 0.01 |
| Sag resistance (max wet mils) | 60 | 40 | Not listed | Not listed | 42 | Not listed | Not listed | N/A |
| No heavy-duty sprayer needed | ✓ | ✕ | ✓ | ✓ | ✓ | ✓ | ✕ | N/A |
| Soap and water cleanup | ✓ | ✕ | ✓ | ✕ | ✓ | ✓ | ✓ | N/A |
| Self-sealing | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | Not listed | ✕ |
| Tear resistant | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✓ | ✕ |
✓ yes · ✕ no. Source: Tower Sealants AU-1 LAB vs. the competition sheet (STS9165).
How the AU-1 system goes on, in four steps
AU-1 sealant and AU-1 LAB are made to work together. Tower calls this the AU-1 Building Envelope System.
- PrepStart with a clean, dry surface. Fill gaps between 1/4 and 1/2 inch with AU-1 sealant. Gaps under 1/4 inch need no prep.
- ApplyPut on AU-1 LAB with a brush, roller or standard airless sprayer. On big walls, spray in a crosshatch. Use a mil gauge to get at least 30 wet mils.
- InspectLook over the surface. Touch up any spots so the layer is smooth, even and free of pinholes.
- FinishClean tools with soap and water before the product dries. Once cured, install cladding or stucco within six months. Stucco can go right over it with no primer.
Download the AU-1 guides
Want all the details in one place? Open or save these guides.
AU-1 Building Envelope System
AU-1 sealant and AU-1 LAB together, plus the four install steps.
You can also find more on the AU-1 sealant page and the AU-1 LAB page at Tower Sealants.
Come see AU-1 in person
Education is the number one thing to a successful project. Come meet the Tower Sealants team, test the product and get your questions answered. We will be at a different store each morning, Monday, Nov. 9 through Friday, Nov. 13, from 7 to 10 am.
Can’t make it? Stop by any Color House store and ask about AU-1. It comes in cartridges, sausages and pails.
The Color House continues to work in the effort to make your projects more successful, both personally and with the professionals you choose to hire.