How To Fasten PVC Trim Correctly

As a mod­ern, inno­v­a­tive alter­na­tive to wood trim, PVC trim is boom­ing. When installed and fas­tened cor­rect­ly, PVC trim can be cut, shaped and just as aes­thet­i­cal­ly pleas­ing as wood trim — with­out all of the dis­ad­van­tages. To set you up for suc­cess, we’ve put togeth­er a guide on how to fas­ten PVC trim to ensure your next project goes smoothly. 

By the end of this guide, you’ll know how to choose the best screws for it and how to fas­ten PVC trim boards secure­ly with a smooth instal­la­tion process. 

What Is PVC Trim?

Polyvinyl chlo­ride (PVC) is one of the most pop­u­lar forms of syn­thet­ic plas­tic poly­mers. It’s used as sid­ing for dec­o­ra­tive pur­pos­es, inte­ri­or pan­el­ing and base­boards, sheets, pipes, mold­ings and many oth­er applications. 

It is often viewed as a low-main­te­nance alter­na­tive for wood build­ing mate­ri­als. PVC trim boards specif­i­cal­ly are often used for appli­ca­tions such as sof­fit, fas­cia, rake boards, win­dow and door sur­rounds, columns and much more. 

PVC trim won’t trim or crack, won’t absorb mois­ture or rot, is pest-resis­tant and can with­stand the ele­ments — all increas­ing the material’s longevi­ty. In addi­tion, it’s a much more afford­able option com­pared to oth­er trim materials.

Collated Cortex® Hidden Fasteners wood-grain plugs being hammered into PVC trim from FastenMaster

Fastening PVC Trim Correctly

Before you start the instal­la­tion, load up your kit with the right tools and mate­ri­als. Make sure you’re using high-qual­i­ty screws that will not suc­cumb to break­age. Use a screw sys­tem that is hard to strip out and has a high lev­el of hold­ing pow­er, espe­cial­ly when using it for larg­er trim boards.

When start­ing the instal­la­tion, secure your fas­ten­ing sys­tem. This ensures the trim boards will not move when the out­side tem­per­a­ture fluc­tu­ates with the chang­ing sea­sons. Just as if you were cut­ting wood, your tools should be sim­i­lar, exclud­ing the fasteners.

We rec­om­mend only using car­bide-tipped blades, but com­bi­na­tion saw blades will work, too. If you use plain steel blades, they’ll dull quick­ly. If you’re cut­ting your PVC trim on-site and not using fac­to­ry edges, we sug­gest you plan your project around the idea that your cut edges will be hid­den since it makes for a clean­er fin­ish. If there are any extra rough edges, you can sand it down with an orbital sander armed with 100-grit paper. A belt sander may melt the PVC as it is plas­tic, so be careful.

Just like with wood, cre­ate over­lap­ping 45-degree joints in areas where the ends of trim meet. Cut the first piece of trim to fall just past the cen­ter of the stud so the over­lap­ping piece can be secure­ly fas­tened to the stud cen­ter. Apply cement to both trim pieces before you ful­ly secure them to the wall.

If you’re installing trim in tem­per­a­tures that hit high­er than 80 degrees, you can fit joints tight­ly. If it gets cold where you’re installing, leave a gap for poten­tial expan­sion and con­trac­tion. Between 60 and 80 degrees, the stan­dard guide­line is a 1÷16” gap for every 18 ft. of length. Below 60 degrees, you should leave a ⅛” gap. Read the fine print of your man­u­fac­tur­er man­u­al to ensure the best accu­ra­cy in your gaps. You can seal the gap with paintable acrylic or polyurethane caulk.

From there, you can begin the fas­ten­ing process. Select the right screws, which we’ll detail in the next sec­tion. Fas­ten­ing well with the right screws helps with expan­sion and con­trac­tion. Make sure you fas­ten to fram­ing, nev­er just into the sheath­ing. Select fas­ten­er lengths that will be able to pen­e­trate the fram­ing by at least 1 ½”. You should place fas­ten­ers approx­i­mate­ly every 16” at both edges of the trim, with spac­ing ½” from the edges. If your trim is 10” or wider, add one more fas­ten­er in the mid­dle. For 16” wide trim, you should uti­lize four screws every 16”. 

Best Screws for PVC Trim

The best screws for PVC trim come from Cor­tex. They come in a kit that includes a bit, plugs and screws. All you do is drill the screw through the trim. Once the desired depth is reached, the bit will com­plete­ly stop the screw. Set the drill down, tap the plug in the hole, and your project is complete!

Cortex Hidden Fastening System for PVC

If you’re installing trim in temperatures that hit higher than 80 degrees, you can fit joints tightly. If it gets cold where you’re installing, leave a gap for potential expansion and contraction. Between 60 and 80 degrees, the standard guideline is a 1/16” gap for every 18 ft. of length. Below 60 degrees, you should leave a ⅛” gap. Read the fine print of your manufacturer manual to ensure the best accuracy in your gaps. You can seal the gap with paintable acrylic or polyurethane caulk.  From there, you can begin the fastening process. Select the right screws, which we’ll detail in the next section. Fastening well with the right screws helps with expansion and contraction. Make sure you fasten to framing, never just into the sheathing. Select fastener lengths that will be able to penetrate the framing by at least 1 ½”. You should place fasteners approximately every 16” at both edges of the trim, with spacing ½” from the edges. If your trim is 10” or wider, add one more fastener in the middle. For 16” wide trim, you should utilize four screws every 16”.  Best Screws for PVC Trim The best screws for PVC trim come from Cortex. They come in a kit that includes a bit, plugs and screws. All you do is drill the screw through the trim. Once the desired depth is reached, the bit will completely stop the screw. Set the drill down, tap the plug in the hole, and your project is complete! Cortex Hidden Fastening System for PVC

The Cor­tex Hid­den Fas­ten­ing Sys­tem for PVC is one of the eas­i­est ways to hide trim fas­ten­ers in PVC.

The TORX® ttap® Dri­ve Sys­tem elim­i­nates the risk of strip­ping out, and the fas­ten­er can be removed eas­i­ly. This sys­tem comes with a sta­bil­i­ty but­ton to ensure your fas­ten­er stays straight through­out the entire instal­la­tion to ensure a prop­er hold. The stronger set­ting tool is great for con­trac­tor use, as the stronger bit mate­r­i­al and indus­try-grade felt allow a 350 fas­ten­er instal­la­tion with a sin­gle Con­text Set­ting Tool. 

The short­er and faster trim screw allows instal­la­tion to be a breeze. The 2” fas­ten­ers allow for pow­er­ful holds and ver­sa­tile instal­la­tions for deck fas­cia and exte­ri­or base­board appli­ca­tions. Because of the dual thread design, the fas­ten­er spins 50% faster, speed­ing up the instal­la­tion process. 

The Collated Cortex Hidden Fastening System for PVC 

Collated Cortex® Trim Hidden Fasteners for PVC Trim from FastenMaster

Like the pre­vi­ous PVC fas­ten­ing sys­tem, the Col­lat­ed Cor­tex Hid­den Fas­ten­ing Sys­tem is great for short­en­ing projects and sav­ing on labor costs.

The fas­ten­ers are avail­able in 2” and 2 ¾” options, both pro­vid­ing supe­ri­or strength and ver­sa­til­i­ty for appli­ca­tions. This sys­tem also has a dual thread design, so the fas­ten­er spins 50% faster than com­pet­i­tive screws, allow­ing instal­la­tion times to be quick­er and eas­i­er. The plugs for the sys­tems also come on a col­lat­ed strip, allow­ing for less han­dling and sav­ing time for work­ers on the job site. 

How FastenMaster Can Help

Through our vast prod­uct offer­ings, you can find the right fas­ten­er for any type of project, regard­less of the mate­r­i­al. Whether you’re work­ing with PVC trim, wood or steel deck fram­ing, we’ve got you covered.


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