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Questions on Doug Fir for a patio

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Forum topic by fastsvo posted 07-10-2020 06:09 PM 490 views 0 times favorited 20 replies Add to Favorites Watch
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fastsvo

8 posts in 30 days


07-10-2020 06:09 PM

Topic tags/keywords: question

Hi Folks,

I have an aging pergola patio cover that has a significant amount of rot and I am in the process of pricing out the lumber. I have been told that I currently have doug fir. Hopefully with the link to my pics below someone could help me confirm that!

Moving forward I am stuck deciding between doug fir #2 BTR & #1 select exposed FOHC S4S “appearance grade” lumber. I am getting a lot of different opinions and the price difference is about 30%. Yes, I do want straight lumber that won’t twist or check and overall look decent, but I can’t help to think that most builders (not customers) would just opt for #2 BTR and then sand the wood down more on-site to get a better look/finish. I am located in Los Angeles area, so we get more sun than rain, but water has not been kind to my existing patio.

In addition, other than the usual prime and paint, what else can I add to the fresh (and old) lumber in order to protect it from water damage? I was thinking I would just coat the bare wood with copper coating and once painted perhaps use some sort of polyurethane (that is UV stable) where I get the most water intrusion (nail heads and simpson brackets)

Any insight and advice would be highly appreciated. Thanks in advance.

https://drive.google.com/drive/folders/14bSXwxYn1drfrTCXDQ7XKgHrRg8pxp0U?usp=sharing


20 replies so far

View LesB's profile

LesB

2573 posts in 4248 days


#1 posted 07-10-2020 08:10 PM

Have you checked out Western Red Cedar instead of Doug fir? It will resist rot better and I think it looks nicer. Either wood would benefit from a coat of deck type sealer/stain every couple of years and for appearance sake after several years clean it with a deck cleaner and brightener and re-seal. There is just no way to treat wood in that situation that will last more than 2 to 4 years. Exterior paint will last longer in some cases but the sun is it’s enemy.

The only thing that will give you long term respite from water damage is pressure treated wood and even with that you need to hand treat any cut ends because the core of the wood does not have treatment.

-- Les B, Oregon

View Lazyman's profile

Lazyman

5655 posts in 2192 days


#2 posted 07-10-2020 08:38 PM

How old is that? I think that the paint may have actually made that worse by trapping moisture underneath. It might have actually lasted longer if it was unpainted so it could dry out more quickly after a rain. I think that attaching to the fascia board also contributed to the rot by having the water coming off the room saturating and infiltrating between the facia, the ledger and the end grain of the beams. I think I would look into different designs that don’t have the issue of water running off the roof into the joints. If you do use a similar approach, you may want to coat the wood on wood surfaces with a paint called red lead which is used by wood boat builders to reduce rotting. There may be better choices for houses.

I agree that western red cedar would probably be a better choice than Doug Fir. I like the look of a rough sawn surface and you can apply a stain if you don’t want the gray appearance that will come within a year or two but you do have to reapply every few years, depending upon your conditions.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

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pottz

10326 posts in 1789 days


#3 posted 07-10-2020 08:41 PM

lesb is right with the cedar i made my patio slats out of cedar 28 years ago and there still in pretty good condition,yes it’s a lot more expensive but as i can see with the condition of your current one it would be worth the added cost.im also in socal and the sun just kills exposed DF.another option would be vynyl or aluminum pergola.all expensive but you dont want to redo this in 10 years again.

-- working with my hands is a joy,it gives me a sense of fulfillment,somthing so many seek and so few find.-SAM MALOOF.

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fastsvo

8 posts in 30 days


#4 posted 07-10-2020 08:59 PM

It Douglasfir is going to have an uphill battle surviving. Would it make sense to spend the extra money on #1 grade exposed wood or stick to #2. Regardless it sounds like it’s gonna need maintenance going forward

View jaipea's profile

jaipea

1 post in 29 days


#5 posted 07-10-2020 10:07 PM

I agree with Lazyman, you have water issues in a bad way, which is surprising for LA.

Dry rot at the base of a pressure treated post (1351) can be helped by using a standoff base to prevent ground contact. With beams butted up against the house with no water protection you need to drill a 1/4” hole on each side of those brackets about 1/2” out from the facia, so water can drain and prevent wood being wet for long.

Protect your end grain with Gorilla Wood Glue or Titebond 3, which are waterproof-rated. Thinning too much will affect the strength, but this is not being applied for strength, so thin to suit the lumber. Most woods will soak up a couple of thin coats, but be prepared to so another before applying a full strength coat. Fares better than any of the end sealers like the anchor or ipe end sealers which are more of a wax surface protectant.

HD’s copper azole treated lumber is brown, and needs no treatment to weather well. If you really really want it white, let it weather for a year before painting. You might consider ripping your own slats from treated lumber and sealing them, but they don’t look in anywhere near as bad a condition as the beams so may not be justifiable.

Pressure treated lumber at HD is so wet it does not absorb well, so overbuy and home dry it for a few weeks. That will give you a chance to cull the seriously warped lumber you do not want to use, and return it to HD.

Do not use nails, pre-drill all holes and use screws. It reduces splitting, and if you ever have to do a repair, way easier to take apart. If you have to cut to length, use original end against the facia.

View fastsvo's profile

fastsvo

8 posts in 30 days


#6 posted 07-11-2020 01:56 AM

Does this look like Doug fir or cedar to you guys?

View pottz's profile

pottz

10326 posts in 1789 days


#7 posted 07-11-2020 02:27 AM



Does this look like Doug fir or cedar to you guys?

- fastsvo


Does this look like Doug fir or cedar to you guys?

- fastsvo

first off i hate when people post tiny pic’s of a piece of wood and ask,whats this.well id probably say DF but the lighting is bad and it’s small so hell it might be oak or walnut,you tell us?

-- working with my hands is a joy,it gives me a sense of fulfillment,somthing so many seek and so few find.-SAM MALOOF.

View LesB's profile

LesB

2573 posts in 4248 days


#8 posted 07-11-2020 06:34 PM

That is not cedar….

-- Les B, Oregon

View fastsvo's profile

fastsvo

8 posts in 30 days


#9 posted 07-11-2020 06:56 PM

No problem, hopefully these pics will be better.

View Lazyman's profile

Lazyman

5655 posts in 2192 days


#10 posted 07-11-2020 08:22 PM

Can’t be sure but it is more likely Doug fir or maybe even just pine.

-- Nathan, TX -- Hire the lazy man. He may not do as much work but that's because he will find a better way.

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fastsvo

8 posts in 30 days


#11 posted 07-13-2020 04:24 PM


Do not use nails, pre-drill all holes and use screws. It reduces splitting, and if you ever have to do a repair, way easier to take apart. If you have to cut to length, use original end against the facia.

- jaipea

I thought screws shouldn’t be used since they have no shear strength?

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fastsvo

8 posts in 30 days


#12 posted 07-13-2020 04:28 PM

A quick question:

I have been reading a lot about letting the wood dry on saw horses, prime and paint it while there and then assemble the structure to prevent wood movement and splitting.

So I just got off the phone with a lumber yard advising me to do the exact opposite. Since the wood will be coming fresh off the mill, they advise to assemble the structure immediately to prevent the movement and then follow up with prime and paint.

I have a two week period until I can get to assembly. Either I take delivery early on and let sit outside on saw horses while I add copper coating, prime and paint or…hold off the delivery until I am ready.

What would you guys do?

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pottz

10326 posts in 1789 days


#13 posted 07-13-2020 04:38 PM

well im getting ready to redo my own patio trellis and im gonna prime and paint before assembly the same way i did 28 years ago,which worked fine for me.i think sealing the wood before assembly is the best way to do it,that way all the surfaces are sealed.im gonna use DF for the posts and beams and cedar for the slats on top.

-- working with my hands is a joy,it gives me a sense of fulfillment,somthing so many seek and so few find.-SAM MALOOF.

View fastsvo's profile

fastsvo

8 posts in 30 days


#14 posted 07-13-2020 04:54 PM

I agree, it so much easier to do all this before assembly and I like the idea of protecting the end grain with glue. I should look into using Cedar for the top slats as well. My (new) plan is to upgrade from 2×2 slats to 2×3 (which they have to rip).

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pottz

10326 posts in 1789 days


#15 posted 07-13-2020 07:38 PM



I agree, it so much easier to do all this before assembly and I like the idea of protecting the end grain with glue. I should look into using Cedar for the top slats as well. My (new) plan is to upgrade from 2×2 slats to 2×3 (which they have to rip).

- fastsvo


yeah 2×3 is the size ive used and like i said mine are about 28 years old.im gonna replace some but most ill just repaint.

-- working with my hands is a joy,it gives me a sense of fulfillment,somthing so many seek and so few find.-SAM MALOOF.

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