Can mdf be used on the exterior?
blownonfuel
| Posted in Construction Techniques on
Discussion Forum
Discussion Forum
Up Next
Video Shorts
Featured Story
Listeners ask about affordable home builds, installing a patio on foundation backfill, and dealing with peeling paint on masonry.
Highlights
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Replies
Not on any job where I've been making the decisions.
No MDF, no particle board. I don't even like finger joints for exterior use.
The slightest bit of moisture and it will swell and crumble.
What would you use it for. If siding or trim, you should probably go with a Hardy Board or similar product, made for the great outdoors.
View Image
Thanks for the answer. I was looking at the Azek website and ran across a picture of crown moulding that was being use on a fascia and it looked liked it was attached to mdf. Maybe it just looked that way but is really something else.
Edited 1/12/2009 4:23 pm ET by blownonfuel
There is an exterior grade of MDF. Buy a piece and stick it in a bucket of water to see what happens.
John
Edited 1/12/2009 4:30 pm ET by JohnCujie
Exterior-grade MDF is fairly common, but expensive. Also, MDO (medium-density overlay) is plywood with a paper facing on both sides. It looks similar to MDF on its face. High quality product.
Justin Fink - FHB Editorial
Although Masonite is not the same as MDO, they both fail with the slightest bit of moisture. Masonite siding was used a lot 20 to 25 years ago. Look at the class action law suit against the manufactures of Masonite siding and I am sure you will make up your mind.
Paul
Although Masonite is not the same as MDO, they both fail with the slightest bit of moisture.
I think you mean MDF.....MDO is used all the time outside without issue.
J. D. Reynolds
Home Improvements
This may sound like a dumb question, but here goes...
Does MDO go by some other name? I've never seen it at any of the local lumber yards (central NJ) and the few times I've asked about it, no one seems to have heard of it.
I'm thinking that maybe "MDO" is a regional name?
I have a job coming up in the spring where I need to replace a lot of water and woodpecker damaged trim. I'm thinking about using Azek, but some are the boards a very wide and Azek will quickly get expensive. That's why I want to look into MDO, but I don't know what to ask for.
Signboard is another term.And some is made for form work. I think that has another name, but not sure what it is..
William the Geezer, the sequel to Billy the Kid - Shoe
Not sure Don......I only know it as MDO (medium density overlay).
J. D. Reynolds
Home Improvements
I keep telling ya, go to a real lumber yard LOL
Huston's has MDO. 1/2", good one side is $45.75. 3/4", good 2 sides is $77.60.
Thanks, Shep. Yeah, I know, I really should shop at real lumberyards more often.
Thanks for the price info too. It's not cheap stuff, but this customer had this trim replaced once before with standard pine trim boards and it didn't hold up. I want to make sure my job lasts for many years to come.
Since MDO has a plywood core, how do you deal with the cut edges?
Not Shep, but as I remember when you rip the MDO it has a real sharp edge because the facing is so thick. You can't really shape it well. You can miter it together, but kind of difficult because you can't really sand the edge when you are done. That's my experience.John
I have also heard it called Creazon.
Almost every time I've used MDO, I've been able to hide the edges behind something else. Its great for the panels under a bay window, or things like that.
Like someone else said, the edge is sharp when cut. IIRC, the face is really a phenolic paper, like a layer of Formica.
Don,
Here's a few links to products that say they have distributors on the east coast.
MDO- http://www.olypanel.com/signMaking/
Exterior MDF- http://www.extira.com/
We use stuff called "Duraply."For a while, Duraply was only putting the paper on one side. Very annoying - we back-prime all our MDO, and getting into the grain and knot-holes was a chore. Now they've switched back to two paper faces, which is nice for other reasons as well.
Don, Huston stocks it in 1/2 and 3/4 4x8.
Rich
The price of oil is way down, therefore Azek should be less expensive also.
Only off by 1 letter
Thanks
I've used Extira, an exterior grade MDF, a number of times. I did some raised panels on a door entry about 8 years ago. I was just at that job, and its holding up very well.
Extira is a sheet product by the same people who make MiraTech trim, which a number of BTers have used with success.
Exterior MDF comes in lumber sizes, 3/4" and 1" net, up to 12". Lengths are 16'. It generally has a wood grain, but you can turn it backwards for a smooth face.
MDO is a plywood and must be ripped to dimension, and can only be 8' long max (I think).
Clear Lam is an LVL product with an MDO face and comes in lumber sizes and lengths. Smooth face only.
The company that makes Clear Lam, also makes an LVL product that is primed, rather than having an MDO face.
John
Exterior grade MDF is also available in 4' x 8' sheets. One brand name is Extira.
Exteria was used to construct 3 of these columns for a client. The frame work and base are Exteria and the fields are a textured concrete panel with a poured in place concrete mid cap. 4 years now and there still fine but they are under big eaves.
Just A Guy With A Hammer
Nice work there brotha.
J. D. Reynolds
Home Improvements
"medex" is the exterior version of mdf.
medex is sold around here for exterior use. I was sceptical so I left a piece on it in the back of my truck for nearly 2 years. through snow and rain other than being dirty it was still in perfect condition
I would have no problem using it for ext trim as long as it was primed and painted
Think green Interstate signs.
Chuck S
http://www.miratectrim.com/pageBuild.asp?PageID=A_product_mI do use it, too.http://www.tvwsolar.com
I went down to the lobby
To make a small call out.
A pretty dancing girl was there,
And she began to shout,
"Go on back to see the gypsy.
He can move you from the rear,
Drive you from your fear,
Bring you through the mirror.
He did it in Las Vegas,
And he can do it here."
This may be a dumb question but is mdf ever used on the exterior of a home?
WHY??
Mike
I use MDO for mitered box columns and exterior panels on bays. Sometimes the wood grain below the paper will telegraph through and you might get a little wave or "football".
I did a two unit townhome with extensive exterior trim back about 1992. Clear cedar was "too expensive" so we tried an exterior grade MDF flat stock for window sides heads and aprons and recess panel frames. After about two years it swelled up about an 1/8" around the nail heads, got a mealy texture, and just looked awful. It all came off and was redone. Never again..............although I am in the middle of some beautiful azek box panel columns!
Thanks Guys for all the answers.
The thing I like about MDF is that after a while you get that nice "cottage cheese" look.
AitchKay
Nice.