#9 x 1-1/4 in. Serrated Flat Head Star Drive Cement Board Screws (185-Pack)
- Serrated head for flush seating
- Star drive with T-25 bit for one-handed installation
- Serrated single lead thread and sharp point for immediate pick up
- See More Details
Frequently Bought Together
Price:
$913
Product Overview
The Backer-On 1-1/4 in. Cement Board Screws are designed for attaching HardieBacker or equivalent fiber cement backerboard to wood or light gauge steel studs. Backer-On's patented serrated head design countersinks for flush seating at any angle, providing a smooth surface for tile. The Star drive recess with T-25 bit provides Stikfit for 1-handed installation. Backer-On screws feature a Climacoat corrosion resistant finish that prevents rust from bleeding into grout and are perfect for use in high moisture areas such as baths, showers, countertops and floors. Conforms to ANSI A108.11 for cement board attachment. Backer-On screws can be installed with a standard impact or drill/driver and T-25 Star drive bit (included with product) for cement board fastening done right.
- Serrated head design for flush seating even at an angle
- Star drive with T-25 bit provides Stikfit for easy 1-handed installation and eliminates cam-outs
- Serrated thread forms require less torque for faster installation
- Patented sharp point offers immediate pick-up and eliminates the need to pre-drill
- Patented design allows attaching close to edge on cement board, drastically reducing fractures or blow outs
- Premium corrosion resistant finish
- Use to attach cement board to wood or light gauge steel studs
- Ideal for use in high moisture areas such as showers, backsplashes, countertops and floors
Info & Guides
Product Overview
- Serrated head for flush seating
- Star drive with T-25 bit for one-handed installation
- Serrated single lead thread and sharp point for immediate pick up
Compare Similar Drywall Screws
 |  | |  | |
| Brand | Grip-Rite | Rock-On | Backer-On | Pro-Twist |
| Name | #8 x 3 in. Philips Bugle-Head Coarse Thread Sharp Point Drywall Screws (1 lb.-Pack) | #9 x 2-1/4 in. Serrated Flat Head Star Drive Cement Board Screws (100-Pack) | #9 x 1-1/4 in. Serrated Flat Head Star Drive Cement Board Screws (185-Pack) | #8 x 1-1/4 in Phillips Flat-Head Fiber Cement Board Screw (1 lb. Pack) |
| Price | $598 | $833 | $913 | $1297 |
| Ratings | (258) | (46) | (248) | (11) |
| Screw Length | 3 in | 2-1/4 in | 1-1/4 in | 1-1/4 in |
| Size | #8 | #9 | #9 | #8 |
| Drive Style | Phillips | Star | Star | Phillips |
| Head Style | Bugle Head | Flat Head | Flat Head | Flat Head |
| Fastener/Connector Material | Steel | Steel | Steel | Steel |
| Features | Coated | Self Drilling,Self Tapping | Coated,Self Drilling,Self Tapping | Coated,Self Drilling |
| View Product | View Product | View Product | View Product |
Compare Similar Drywall Screws
| | | | |
| Brand | Grip-Rite | Rock-On | Backer-On | Pro-Twist |
| Name | #8 x 3 in. Philips Bugle-Head Coarse Thread Sharp Point Drywall Screws (1 lb.-Pack) | #9 x 2-1/4 in. Serrated Flat Head Star Drive Cement Board Screws (100-Pack) | #9 x 1-1/4 in. Serrated Flat Head Star Drive Cement Board Screws (185-Pack) | #8 x 1-1/4 in Phillips Flat-Head Fiber Cement Board Screw (1 lb. Pack) |
| Price | $598 | $833 | $913 | $1297 |
| Ratings | (258) | (46) | (248) | (11) |
| Screw Length | ||||
| Size | ||||
| Drive Style | ||||
| Head Style | ||||
| Fastener/Connector Material | ||||
| Features | ||||
| View Product | View Product | View Product | View Product |
Specifications
Dimensions
Screw Length
1-1/4 in
Thread Pitch
0
Details
Color Family
Green
Drive Style
Star
Fastener Plating
Zinc
Fastener Type
Drywall Screw
Fastener/Connector Material
Steel
Features
Coated,Self Drilling,Self Tapping
Finish
Zinc-plated
Finish Family
Zinc
Head Style
Flat Head
Included
Driver Bit
Interior/Exterior
Interior
Measurement Standard
SAE
Package Quantity
185
Product Weight (lb.)
1.16
Returnable
180-Day
Size
#9
Warranty / Certifications
Manufacturer Warranty
ITW Brands warrants that this product is free from defects in material and workmanship. ITW Brands’ sole liability for any breach of this warranty shall be to replace this product or refund the purchase price.
Questions & Answers
8Questions35Answers
Can I use these for a toilet flange?
Asked by Jm May 2, 20201
AnswerThese would be strong enough but I am not sure if the length would be sufficient for a toilet flange. It depends on your subfloor as well.
Can I use these screws to fasten cement board to .050” thick aluminum square tubing?
Asked by Jeff April 20, 20203
AnswersI used them to put Hardeeboard onto wood studs. Assuming any normal screw would go into aluminum then yes. But honestly I'm not sure.
Can I use these for hardie siding?
Asked by Juan June 19, 20194
AnswersYEs, that's what they are for.
I am attaching Hardie backer to 1 x 2 furring strips on concrete block. I measured the thickness...
Asked by JJB February 26, 20195
AnswersThe screws are a full 1.25". The standard half inch Backerboard is actually just 0.42" so you're going to be 0.12" too long which is more like 1/8".
I cannot get the serrated head start drive cement screws into the backer board. I have even tried...
Asked by Iisahandy September 2, 20189
AnswersLisa, I assume you are using the correct driver which came in the box of screws. Some of the screws use a Phillips head and some use a star shapes head. The bit that came with the screws is the one you need to use. I have used these screws and the cement board about a gazillion times and never had the problem you discribe. If you are using the correct driver but and you can't get the screw started, try drilling a hole smaller than the screw diameter. Set your drive on low speed and firmly press down on the screw head pushing straight down. The cement board Hardie Board, is actually rather soft and drills rather easily. Once you get the hang of drilling a pilot hole for the first couple of screws you will get the hang of it and not need to drill a hole first. Good luck
Has anyone used these to fasten cbu to steel studs (20 gauge or thicker)? Did they self-tap as stated?
Asked by CitizenSnips May 6, 20183
AnswersNo we used on wood
How many square feet of 1/4" backboard would this box cover?
Asked by doorguy November 29, 20175
Answers28 screws are NOT enough. I believe there are 56 dimples on each full board. Don't scrimp. At 5 cents a screw, you are only saving $1.40 a sheet.
Coverage..
Asked by Ajsk August 15, 20175
AnswersDepends on how many you use per sheet I like to use one every 6 inches vertically and horizontally 77 screws per sheet so almost 10 sheets
Customer Reviews
Overall Ratings
Excellent Screw for any backer board
July 27, 2020
Every screw is perfect. Of course when I hit a nail head underneath then the screw cannot penetrate, but that was rare. This screw made the entire backer board project ALMOST fun! The tip easily penetrates, and the screw head has a digging action which makes the flush setting that-more-easier.
Worked just like it was recommended on video about Hardie Cement Board
April 30, 2019
Worked just like it was recommended on video about Hardie Cement Board
Forget it if you wanna put 1/2” hardie board
April 16, 2019
Cheap and flimsy. It won’t go through and lots of energy to work with. Should have stick with GRKs. Wanted to try these but now I know what a junk they are.
Awesome screws for use with Hardy board. It cuts thru the board quick and doesn't split the mater...
March 26, 2019
Awesome screws for use with Hardy board. It cuts thru the board quick and doesn't split the material.
Love these screws; very versatile and they stay in bit...
November 13, 2020
Love these screws; very versatile and they stay in bit so you can use your free hand to stabilize whatever you are securing.
Rating provided by a verified purchaser...
November 11, 2020
Rating provided by a verified purchaser
The perfect board screw for the hardie board....
November 10, 2020
The perfect board screw for the hardie board.
Rating provided by a verified purchaser...
October 26, 2020
Rating provided by a verified purchaser
Rating provided by a verified purchaser...
October 24, 2020
Rating provided by a verified purchaser
Cement Board Screws
October 20, 2020
These screws worked great for attaching 1/4" cement board to the wall. These did not require any pre-drilling and easily sank into the board and sat with the head flush with the top. Super easy to use and its great that these are T25 heads - much better than phillips
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