Questions on Doug Fir for a patio

Help Support House Repair Talk:

fastsvo

Member
Joined
Jun 6, 2018
Messages
22
Reaction score
1
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.

Patio - Google Drive
 

havasu

Administrator
Staff member
Admin
Moderator
Supporting Member
Joined
May 20, 2010
Messages
4,129
Reaction score
139
Looks like a combo of termites and dry rot. Have you treated your home yet?
 

Snoonyb

Well-Known Member
Joined
Sep 30, 2006
Messages
3,921
Reaction score
749
In all probability, it's DF and just #2 and better.
As suggested, you should be checking the rafter tails for termite damage.
 

Jeff Handy

Well-Known Member
Joined
Nov 20, 2019
Messages
564
Reaction score
153
Location
Chicago suburbs
Use the newer type of treated wood without arsenic.
Copper and ammonia, and kiln dried.
Or else buy twice the wood you need, lay it out to dry for two months, and use the best, return the rest

Let it weather for at least three months, then apply semi-transparent stain.
 

fastsvo

Member
Joined
Jun 6, 2018
Messages
22
Reaction score
1
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?
 

Jeff Handy

Well-Known Member
Joined
Nov 20, 2019
Messages
564
Reaction score
153
Location
Chicago suburbs
I would not put the wood on saw horses, it will sag.
Lay it out on the patio.
Turn the boards over a few times if you can.
Buy lots of extra of each size.
Bring back whatever twists or bends the most.

Yes, if you are installing decking you can nail it or screw it down wet, and it will have nowhere to go, with so many fastening points.

But your pergola has long unsupported spans, you will have lots of banana boards up there, IMHO.

Or find a yard selling kiln dried, and also pressure treated if available.
You will know what it will look like forever.

There are also treatments that you can paint or dip onto any cut surfaces of pt lumber.
Or can be used for regular lumber in areas that will stay moist, or where pieces cross or double up, or contact with the patio or house.
 

fastsvo

Member
Joined
Jun 6, 2018
Messages
22
Reaction score
1
I would not put the wood on saw horses, it will sag.
Lay it out on the patio.
Turn the boards over a few times if you can.
Buy lots of extra of each size.
Bring back whatever twists or bends the most.

Yes, if you are installing decking you can nail it or screw it down wet, and it will have nowhere to go, with so many fastening points.

But your pergola has long unsupported spans, you will have lots of banana boards up there, IMHO.

Or find a yard selling kiln dried, and also pressure treated if available.
You will know what it will look like forever.

There are also treatments that you can paint or dip onto any cut surfaces of pt lumber.
Or can be used for regular lumber in areas that will stay moist, or where pieces cross or double up, or contact with the patio or house.
problem is that I don't have a truck to return extra wood, so I have one shot to do this right ;)

I have seen some of the elastomeric treatements and the idea of thinning out wood glue on the end grains as well.
 

fastsvo

Member
Joined
Jun 6, 2018
Messages
22
Reaction score
1

Jeff Handy

Well-Known Member
Joined
Nov 20, 2019
Messages
564
Reaction score
153
Location
Chicago suburbs
You definitely want to hand pick any boards that will be long horizontal spans.

If they have a big knot, they will sag due to that weak spot.

You can also drill out a big knot with a bigger hole saw, and insert a tight fitting wood plug, adhered with exterior carpenters’ wood glue.
 

MrMiz

Junior Member
Joined
Jan 11, 2009
Messages
88
Reaction score
31
For me the difference is how the wood is being used. Wet wood that has a structure(more screws, braces, brackets etc) to secure it is better to use while it's wet. Be cause there is some force involved in keeping it in compliance. Like if your going to be building a deck and your going to be joining boards at all locations for the best structural stability. On the opposite end if it's going to be secured via just a tongue and groove join. (relatively thin boards) and a a few brad nails in the field then you need to let it dry and then work it into place so the T&G joint doesn't get "surprise" binding which will cause it to buckle/pucker. Think flooring and decorative ceiling boards like this:
TNG.jpg

You want absolute minimal movement after installing because there really isn't much structurally keeping in in place like with a deck. If you allow treated decking lumber to dry without securing it your going to loose about 35% (in my experience) to warping that will make the board completely unusable after drying. However the same boards if they are "strong tied" and braced then a top decking additionally is attached it will still warp a little, but rarely enough to change your structure.

As far as what kind of products to use, and where. I feel like this is more of a budget/preference question than anything else. Do you want to add color, transparent, or paint? Is it time to look at a product like Trex for visible surfaces? Are you ok with yearly maintenance? Would you rather spend the money up front on new decking or in maintenance over the years (maybe even paying somebody to do if for you)? Is the sub structure up to the task of holding new decking or are you just "putting lipstick on a pig" because it's just easier to brush something on? Those are the question that go through my mind when you talk about what to use on existing and old wood. If you ask a contractor the answer is going to be "replace and fix", if you ask your brother-in-law who is there to help for a couple of beers then the answer is " I heard about this great new product that you just paint on and you never have to do anything again"... this leaves you somewhere in the middle.

My 2 cents and how I do it.
 
Last edited:
Top