Brick Molding*
How to make it last <maybe> 50 years
by Joe Mehaffey

The usual material for brick molding, soffit and Fascia trim on homes is wood.  Long ago,  hardwoods were used for these applications and in some cases the painted wood would last for 50 years without serious rot and deterioration.  Now with the use of untreated fir, pine and other relatively softwoods for these trim applications,  noticeable rot can be found in 5 to 10 years in many (if not most)  uses of soft woods in these applications.

In my own home,  I had rotten brick molding in just 5 years and now at 8 years I am replacing all of it.  While dissecting the damaged windows, I figured out that the major problem causing such early failure of the brickmolding  was that the window installation had been done improperly in the first place.  There was no metal flashing around the wooden brickmold to keep the wood from touching the brick,  There was no metal flashing on TOP of windows in siding walls to keep water from running behind the brickmold,  there was no paint on the brickmolding except for the exposed outer surfaces and there was no paint or sealant of any kind put on the cut edges at the corners.  This was just poor workmanship and the combined faults made for an ideal breeding ground for rot.  Had all of the above steps been taken with the original installation,  this premature (and expensive to repair) problem would not have happened.

I decided that using soft wood for the repairs was just going to be an ongoing maintenance problem and so I have researched other materials.  The current local cost of standard brick molding (finger jointed) is about $0.65 per foot,  stain grade (not finger jointed) about $1.05 per foot,  Royal Wood about $1.20 per foot and Solid PVC about $1.40 per foot.  Therefore,  the cost of brick mold materials and caulk for the average window ranges from about $30 for wood to about $49 for solid PVC.  Labor costs to PROPERLY remove old brick mold and  install replacement brick mold average about $80 per window in the Atlanta Area.  (This includes teardown, caulking, cutting new brickmold, sealing in place and painting.)   Thus,  if you elect to pay about $129 per repaired window for new brick molding using solid PVC instead of $110 per window using wood,  you can expect perhaps 50 years of life for the PVC brick mold instead of 5 to 15 years.  See examples of rotting window molding  HERE.

Brick molding lifetime is estimated as follows:  1) Wood, caulked, and paint only the outside of the wood, 5 to 8 years,  2) Wood, caulked and painted on all surfaces including the cut ends before installing with proper flashing and sealing,  15+ years,  3) PVC brick molding installed in accord with instructions below, 50 years.

I have found that there are at least three options for "wood looking"  trim as follows:

    The typical wood trim on homes will be found to be white or yellow pine.  These materials absorb water and, with IMPROPER installation may rot in just a few years despite conventional attempts to caulk them  against leakage at their interface to brick or siding. PROPER construction technique will require painting of ALL exterior wood trim back, front, top, bottom and ends BEFORE the trim is installed and installing metal flashing so the wood cannot touch the brick.   Most often,  the wood brick molding is not painted (except on the exposed sides) or otherwise treated to protect it from rot.  Very frequently, the metal flashing needed around the wood molding parts to keep the molding from touching the brick and to steer any water toward the outside are omitted.   EVEN WORSE  are  finger jointed brick molding materials which  provide a haven for the beginnings of rot every foot or so along the entire molding at the finger joints.  If not painted all around and properly flashed,   bare wood normally is in contact with the porous brick (see above photo).  If the molding is not painted all around the wood piece and protected from contact with the brick by flashing,  the molding's bottom surface will remain damp for long periods after rains and rot can progress rapidly.  If you MUST use wood for trim,  you should paint all sides of the molding with good primer  plus a coat of paint BEFORE nailing it into place, provide metal flashing all around to prevent molding contact with the brick  and then use great care to caulk and seal the joints and especially the contact points with the brick, siding, and flashing.

Other much longer lasting options for brick molding now include PVC extruded over plasticized wood dust (example:  ROYAL WOOD) and PVC (Polyvinyl Chloride) extrusion, example: SOLID (foam interior) PVC PLASTIC)(Available Colors HERE).  Either of these is to be preferred over wood.  See photographs of these materials below.  Royal Wood is the material with the wood center;  Solid PVC is in the lower part of the picture with the white center.  (Note: Similar products may be available from other vendors.)

Royal Wood (top with wood center and extruded PVC skin) and Solid PVC (bottom with solid PVC center)

The "Royal Wood" brand material is a plasticized wood dust mixture inside with a thin PVC "skin" extruded over all.  This comes in various shapes including standard brick mold shape.  This material is somewhat cheaper than solid PVC brick molding and can be sawed and nailed generally like wood.  Its wood dust interior is filled with a mixture of wood dust and plastic glue at the time of extrusion and so the core will not absorb water.  Our experience with this material is that while it likely will have a lot longer life than wood,  it can  split when nails are driven into it. (See photo HERE.)  Sometimes driving a nail will break the solid wood+plastic core and the  plastic skin and sometimes it just causes a crack in the wood dust core and does not quite break through the PVC outer covering.    Either way,  it is not good to crack the inner core as this will stress the outer skin which can lead to cracking.   Another problem I ran into with Royal Wood is that in some windows,  the wood framing of a structure may "settle" about 1/16 inch relative to the brick veneer outer walls.  This requires that the bottom edge of the brick molding  be trimmed (using either a belt sander or a table saw) to make the replacement molding fit between the lower edge of the window and the brick ledge.  The plastic tends to melt and  gum up the sanding belt and so the saw is preferable.  However,  sawing off 1/16 inch of Royal Wood exposes the wood core all along the bottom of the molding.  While the manufacturer says this is OK,  I did not like this feature as the edge of the outer skin then tended to pull away from the wood dust core.  All in all,  I think this material should only be used for NEW work and then not unless the carpenter is willing to drill holes for his finishing nails (or use nails smaller in diameter than the 1/16 inch diameter finishing nails we were using) and where it is not necessary to trim the molding's height to fit between the brick and the window frame.


The Solid (Foam Center) PVC brickmold is my favorite.  It is solid PVC plastic (same as used in the white PVC schedule 40 water pipes you see everywhere).  Like Royal Wood, Solid PVC is impervious to insects and  rot and is highly resistant to sunlight even if not painted.  It is as easy to cut as wood and, if needed, can be shaved easily to fit into a reduced height space under a window as noted above.  I really have no downside to report on the SOLID core PVC brick mold products I have used.  In the past,  I have seen "hollow" or "air core"  PVC moldings.  They are less easy to use and offer no that advantages that I can see.  It is easy to "squeeze" these hollow shapes when nailing them and distort the outside contour.  I have not seen these "hollow" moldings offered locally in several years.  A cross section of the Solid PVC brick molding I use can be seen below.  The Solid PVC is the "all white center" molding in the bottom of the photo.  In past uses,  I have used "really solid" PVC brick molding but this is no longer available in our area and I see no advantages to it as compared to the PVC brickmold pictured above with the foam PVC interior.

Removal of OLD and Installation of the NEW Molding

The method used in installation of the NEW molding is extremely important.  Even if you use the solid PVC molding recommended,  making sure that WATER stays OUT of the area around the window is all important if you are really interested in your new installation being as MAINTENANCE FREE as possible for the long term.  Often,  brick masons fail to provide adequate slope of the brickledge (the ornamental brick directly under the window) toward the outside.  This can allow water to puddle against the brickledge and seep under the brickmolding if the brick molding to brickledge  gap is not sealed.  Completely sealing the bottom edge of the brick molding to the brick will prevent water entry under the brick molding even in cases where the brick ledge is misinstalled.  On new installations (even with PVC),  it is a good idea to use some metal flashing against the brick, at LEAST on the bottom and a few inches up the sides to absolutely move any water which does penetrate the system in later years back toward the outside.  It is difficult to do this on some repairs and it is for this reason that we were forced to use a lot of Silicone Caulk so as to provide multiple barriers to water as the window system ages.

The following steps apply to those (Most I think) installations where the metal flashing was left out at the time of original construction.  The steps for a water tight installation are straightforward,  BUT you may well get advice from some installers (such as those who messed up the installation the first time) that "all that caulk is not necessary".  Listen to them and water MAY get in behind the molding and rot your windows and/or the sheathing and framing members around your windows even if the molding itself will not rot.  In my own home,  water had been dripping out of the top of a lower story window during exceptional blowing rain.  It was determined that the "edge seal" at the bottom of the brick molding on the window directly above had developed a small "crack" in the caulk between the brick ledge and the brick molding.  During a heavy rain,  water was being blown into the crack,  inside the wall behind the brick and into the window structure on the floor below.   Better to do it right and SEAL the window as described below and prevent water getting beyond the molding and you should get MUCH LONGER life of the entire structure.  The only downside to using lots of caulk (aside from the extra cost of the caulk)  is that if you ever have to remove the molding,  it may well have to be sawed out in pieces.  But the extra structural life you get from a good seal will make any extra work later worthwhile.

Removing Old Molding

The removal of the old molding can be easy or difficult depending on many things.  Typically you can make good use of a SawsAll or hand Router and some wood chisels and small wrecking bars among other things.  The router turns out to be considerably faster than a SawsAll and there is less danger of cutting into the structure behind the brickmold if a router is used to break up the old molding.  Use GREAT care not to strike your brick or siding with a hammer or other tools or you may cause significant damage.  Sometimes the wooden frame structure will have settled and pinched the bottom brick mold piece between the brick ledge and the window.  In such cases,  you will have to use the Router or SawsAll to cut a slit all along the bottom piece of molding so as to be able to remove the piece.  At other times,  the molding will pop right out with a little coaxing from a pry bar.

Installing the NEW PVC Molding and getting a robust water seal

The basic idea is to provide multiple seals against water entry around the brick molding.  The first step is to completely seal the gap between the brick and the sheathing behind the brick along the brick ledge (across the bottom of the window) and then up each side several inches to prevent water getting between the brick and the sheathing behind the brick EVEN IF WATER GETS UNDER THE BRICKMOLD.  This will prevent any water that does get by the brick molding in the future from getting down between the brick and the sheathing.  The second step is to seal the brick mold to the brick ledge and to the sides and top brick surfaces with caulk and also to seal the joint between the brick molding and the window assembly with caulk.  Also,  to be sure to coat the cut ends of the brick molding with caulk so water cannot enter at the corner joints.  Finally,  (after painting as needed),  to seal the exterior joints between the brick molding and the brick and between the brick molding and the window unit.  This "triple seal" should prevent water entry into the window area for a long time to come.

1) You will need from 4 to 6 tubes of GE Silicone II clear caulk per window.  Clean the old Caulk thoroughly from the brick or siding and from the window frame as required.  (Note:  You can use other caulks but my experience with Silicone II is that it is more elastic than most other caulks and adheres very well to brick,  PVC and most other building materials.   Silicone II lifetime is rated 50 years.  GE Silicone I and other brands of all silicone caulks are almost as good. Cutting corners on quality caulk is false economy if long life of the molding is your goal.  Also,  use care NOT to get this caulk on the OUTSIDE surfaces of the brick mold as most paint does not adhere well to it.  You will be using another bead of PAINTABLE caulk on the seams of the molding  on the outside and at the juncture of the brick mold and brick and window and brick mold AFTER the brick mold is installed and BEFORE painting.)
2) Use the silicone II caulk to thoroughly seal the gap between the brick ledge and the wood sheathing behind the lower molding.    Also seal the gap on both sides up at least a foot above the bottom ledge.  This will prevent water (which may later enter through cracks in the caulk) from getting down into the wall spaces between the brick and outside sheathing.  Use foam insulation or some rope material to fill the gap if it is too wide for a bead of caulk to bridge alone.  Be liberal with the caulk and make sure it adheres well to the brick and to the sheathing behind the brick.
3) Cut and fit the four pieces of molding so that they are a good fit (fairly tight with minimum gaps) around the window.
4) Place a thick bead of caulk on the brick under where the new molding will fit all around the window.  Be especially liberal with the caulk on the bottom brick ledge and several  inches up the sides of the brickmold opening along the brick casing.  Make SURE to work the caulk on the brick ledge surface well into the brick to assure adhesion and to seal  the rough mortar joints.
5) Select the BOTTOM piece of molding.  Put a small bead of caulk on the top of the molding and on the cut ends.  Install the bottom piece of molding using care to insure that there is a good seal of the molding to the brick (or siding) and also to the window frame on the top of the molding.  Center the molding and nail into place.
6) Similarly,  place a bead of caulk on the side molding pieces (including coating the cut ENDS of the molding) and insert them into position and nail into place.
7) Caulk the top piece of molding and insure that it, too, has sufficient caulk to seal it to both the window and to the brick.
8) Immediately wipe away any excess caulk from the outer surfaces of the brickmold,  window sash and brick (or siding) surrounding the brickmold.  Do this immediately because if you leave Silicone II caulk on the surface,  paint has trouble sticking to the caulk.

Finishing Your Work

After allowing the installation to "cure" for a day or more,  you still need to seal the outside joints of the molding, fill the nail holes and (perhaps) paint the new molding as well.  Since the PVC molding is white, (or perhaps some other matching color),  painting may not be necessary.   If painting is NOT required,  I suggest using Silicone II clear caulk on the joints and GE  Paintable caulk on the nail holes.  If painting IS required,  I suggest using the GE Paintable caulk for both the nail holes and on the brick to molding cut joints as well.  If you decide to paint the PVC brickmold or Royal Wood,  be sure  the new brickmold is cleand and  use a special PVC primer such as Sherwin Williams B66-A50 bonding primer otherwise your paint may not stick securely to the PVC.

Where to find Materials and Installation Expertise

The PVC brickmoldings and GE Silicone Caulk are available at  building material dealers nationwide.  The PVC brickmold may not be available at dealers such as Home Depot and Lowe's.  However,  most full service building material stores  frequented by builders will have it or can order it from a local jobber.  These dealers should also have PVC crown molding (up to 6 inch),  base molding and several other shapes in PVC.  3/8 and 5/8 inch PVC panels come in sizes to 4ft x 18ft andvarious size planks for use in replacing  plywood in bay windows,  soffits, and similar exterior wood trim.  When installed and painted,  these products look just like wood,  but they do not rot, warp, twist or split as wood has a tendency to do over time.   Locally here in the North Atlanta, Georgia, area,  I purchased solid PVC brickmold  and other PVC materials at Midway Building Supply.  (Stan, phone 770-475-7067).  Any good trim carpenter can install new brickmold and other PVC trim.  Just be intent on hiring a man who is WILLING to do it right.  Many carpenters are unable to do a quality job cleaning, sealing, correcting problems found, and installing brickmold properly sealed because they are not willing to take the time it takes to do the job right.  If possible,  avoid these folks and get a man willing to do the job on an hourly basis and take his time to do the job as described above.  The PAYOFF will be in never having to replace the brickmold again.  A master trim carpenter  I use in the North Georgia area is Tim Bowden 706-974-7347.

Update May 2011:  I continue to replace rotted and failed WOOD trim on my buildings.  But.. I have never replaced a single piece of PVC trim I have had installed and some of it is now 10 years old.  There is no buckling, rotting, twisting, or warping of any of the installed PVC.  I have left some UNpainted using stainless steel nails for 5 years and it still looks like the same day it was first installed.  Yes.. PVC is a good material for "wood like" trim that you want to last a lifetime!

Questions?  Comments?   Suggestions?

Email Joe Mehaffey                          *This article and photographs Copyright 2002 by Joe Mehaffey