exterior trim boards- what material?
starboardtacker
| Posted in Construction Techniques on
I’m considering running pre-primed white pine trim boards (Primelock) on my rakes, fascias and soffits. Originally I was thinking red cedar, but i’m trying to keep cost down. Will the Primelock hold up? Are there any other alternatives?
Replies
white pine rots out fast in our climate..even if it's backprimed
we use Georgia Pacific PrimeTrim almost exclusively... more decay resistant than cedar or redwood, cheaper than pine, loves paint.. downside.. use mostly butt joints , it doesn't like being edge nailed and it likes solid support
Mike Smith Rhode Island : Design / Build / Repair / Restore
I read in some magazine ( forget which ) about using a plastic mold wood stlye material for trim. It was right size. cut easy and could get it in colors. Where ? I cannot tell you.
Mike,
I'm leaning your way for an upcoming project. For the butt joints do you do anything special to the GP PT? Biscuit? Simple butt? Caulk?
How are the corners on the boards...sharp or eased edge...ie, when butted end-to-edge, it it a nice flat seam?
Is there a discernable difference between painted end and edge "grain" at a butt joint?
Does any certain primer/paint combo work best on this?
Thanks much, I'm off to their website to get propaganda-ized.
Mongo
i'll take some close ups and show you...
me and my lead carp. disagree on this.. he wants mitered edges.. i don't.. so far, he lets me win.
my observation is that the GP Primetrim has no strength thru it's thickness, so it doesn't like edge nailing , it only responds well to surface nailing on the flat..
Piffen says that he has used a lot of GP PT.. maybe he has some tricks up his short sleevesMike Smith Rhode Island : Design / Build / Repair / Restore
They recommend not nailing at ends. For instance, on an outside corner joint we fit it, then use urethyne glue and nail back from the corner after predrilling. As I think back, I can't remember many butt joints, Victorian style has a lot of corners, allowing you to use short pieces.
I think it does expand in both directions, so it seems that a butt joint would need a control caulk space. But I'm sure that it expands less than real wood by far. It just doesn't seem to absorb muych moisture.
Since it's floppy, it definitely needs subfascia and a gutter man needs to know about it's peculiarities.
It'll chip and flake at edges. It comes with an angle relieved edge on it. You can get it in full inch thickness too, which is two layers factory laminated. The dust sucks, and you will too, for iar, if you don't wear a dust mask and end up with a snootfull.
I use a lot of Prime lock too. Much easier to work with but I don't know if it's that much cheaper than red cedar. Maybe half price but that's only a couple hundred on an ave house, right? This photo is done with primetrim on the water board skirt and the upper fascias etc. The middle wall trims are all pine.
.
Excellence is its own reward!
here's a pic of a 5/4 x 6 corner board....and in the background is a 5/4 x 4 window casing on a Trex sill.. the siding is Certainteed Cedar lap at 4" exposure.. painting & puttying by OwnerMike Smith Rhode Island : Design / Build / Repair / Restore
I use a lot of PrimeTrim too... matter of fact just put up some rakes today. I use miters for scarf joints and outside corners, but only were they are out of harms way. The stuff does tend to break off easily. I've never noticed much movement even in long pieces, even in some jobs a couple years old. A couple of my tricks...
I use pre-primed pine for the soffits instead of PrimeTrim (too floppy), and we rout a 1/4" deep groove in the fascia to lock the two together. Mostly use stainless trim head screws, but use some galvanized nails in a Paslode finish nailer.
If we are doing stucco we pack out the rakes and eaves returns with 3/4" pine. Mostly I use 1x8 rakes, so we will use a 1x6 pre-primed pine board as a packer and line the tops of both to the roof sheathing. This leaves a nice space under the rake for us to run the stucco wire into, and the stucco finishes right to the underside of the trim...looks good and more waterproof.
We treat the "volcanos" made by the fasteners like any other MDF...chisel them flat, spot prime, fill, sand, and spot prime again.
here's some more pics of GP PT..
the green ones (GPPT )were installed and painted in '95.... scarf joints, and butt joints , and a good example of a concealed but bulging split from someone who insisted on end nailing to close the joint
the white ones are some work-in-progress..including the craftsman style colums.. all GPPTMike Smith Rhode Island : Design / Build / Repair / Restore
Mike, thanks so much for going to the effort of posting the pics.
To the rest, thanks for the additional info.
I spent a while on their website last night, a GP rep is going to stop by next week with a few sticks for me to check out.
Based on the description of the manufacturing process that I read on-line, it pretty much sounds like an MDF-type material that can handle the outdoor weather.
I didn't see any reference to weight or density though. Is it heavy like MDF?
Again, thanks to all for the input.
Mongo,
It is more like Medex. MDF is not water-resistant and shouldn't be used for exterior. Primetrim is similar density, workability, and nasty dust but handles water well..
Excellence is its own reward!
I understand MDF can't take the weather. I was trying to get across that I inferred from the site that GP PT is similar to MDF in composition...in that the manufacturing processes are pretty similar...but GP PT can also take the outdoors...unlike MDF.
Thanks for the follow up.
Right - processing same..
Excellence is its own reward!
Good shots, Mike. I've got to start getting more close detail pictures. What is the degree of angle on the column? if you know of the top of your head?.
Excellence is its own reward!
no .. i don't .. but it tapers from a boxed 4x4 at the top to a 10x10 base...in about 5' (?)Mike Smith Rhode Island : Design / Build / Repair / Restore
I have used,, on two applications, the PVC door jam material made for garage doors. If you reverse them, the back is fluted and makes a good looking material to look like fluted pilasters or a fluted corner. There are also white Structoglas 4 x 8 panels that might be used for a trim board. This has a shiny pebble finish but can be reversed for a flat level white finish. This material is made for industrial use and even shower stalls so moisture would never be a problem. UV might eventually be a problem. But it could then be painted. Surely if it had to be painted it would hold paint better than the finger jointed lumber sold for trim boards.
yup... better than the FJ... but this is GP PrimeTrim, which is very decay resistant and loves paint, comes in about 10 different dimensions including 4/4 & 5/4.. comes in 16' lengths and it costs less...
if you can design your details to take care of it's weak points... it's great stuffMike Smith Rhode Island : Design / Build / Repair / Restore
Have you tried Azec trim?
Richie