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-   -   Need to replace rotten wood support post on porch (http://www.diychatroom.com/f19/need-replace-rotten-wood-support-post-porch-144072/)

cdnNick 05-17-2012 11:57 AM

Need to replace rotten wood support post on porch
 
I had a nice surprise last weekend when I went to paint the wood post on our front porch, as I went to strip the paint I found out the wood underneath was wet and rotten. So now we need to replace this post which supports the porch roof and about 2 feet of the 2nd floor stick out above the porch.

We called a contractor in who suggested using a fiberglass post which sounded good to us but his quote was really high and didn't include re-installing the two rails that are attached to the post, so my wife and I started to look around at options and Home Depot has a fiberglass post that will support 10,000 lbs which I thought was same as the contractor suggested. HD didn't have much info on the posts so I contacted the manufacturer for info and they said the posts are not meant for anything other then carrying the load of a roof and that since some of the house was supported on the column we would have to add a metal post inside the fiberglass column.

Now I am wondering why the contractor only suggested the fiberglass post which in our case would void the warranty since it will support part of the house, and maybe I should just go with a metal jackpost and buy a vinyl column or build a box around it.

Does anyone have any experience with the fiberglass columns and was the contractor talking about a different product that could actually support the full load without the need for a metal post?

bill01 05-17-2012 01:35 PM

How big is the wood post you are going to replace. Why would you suddenly need a steel post when wood was working.

It would be silly for them to try to word it to support a roof only. What happens if I have a huge roof supported only on the corners with these columns and use cement tiles.

They key is making sure your load you are try to support is less than the products limit. 10,000 lbs is quite a lot so it may be fine you just have to do the math or figure out what the maximum for your wood post is.

You might very well be able to use a wood post inside..all depends how big you are talking, those big 1 ft around columns or a 4x4 post.

cdnNick 05-17-2012 01:45 PM

Sorry, I should have mentioned the wood post is 5 2x8 nailed together. The fiberglass post we were looking at is 8" square they also have a round version. We didn't want to use wood again because it will rot again, especially around the base we get snow buildup in the winter and it's sitting on a concrete porch.

This is in the product listing: Load Bearing - Roof Loads Only!
Void Warranty - Structural applications where people are supported: Balconies, floors, stairs etc.


We looked at a vinyl clad system that has a metal post inside but was only rated for 4500lbs which I think may be undersized.

bill01 05-17-2012 02:39 PM

Yup that is a lot of weight. This table says a 8x8 wood column would support more than 50,000 lbs. Hard to say how much less it not being 1 piece of wood would be. Strange you have rot issues. I have had pressure treated lumber I pulled out of the ground after 10 years and the part that was in the ground almost new.

Wood is very strong in compression and fiberglass is not. I can see why they want a steel post.

https://courses.cit.cornell.edu/arch...7.1/index.html

cdnNick 05-17-2012 03:11 PM

The house is 17 years old and I'm not sure what kind of wood they use but the way it was installed is not allowed anymore by code so.
** EDIT: It was installed directly on the concrete, now there has to be some kind of barrier between the wood and concrete.** We walked around the area and lots of house have replaced the columns. The jackposts I looked at were rated for ~8100lbs.

bill01 05-17-2012 03:33 PM

You may want to look at simpson site. They make column mounts that hold the wood just off the concrete. The largest I see is for 6x6

http://www.strongtie.com/products/connectors/ABW.asp

Duckweather 05-17-2012 05:34 PM

Is the part of the house overhanging a second floor that hangs over an exterior wall 2 feet? If so it must be a cantilevered second floor and much of the weight is already carried by the floor design. If not the posts would have to be under the overhang to support the weight. It should not be supported by the roof. You can replace the post with the same 2 x 8 s in pressure treated and make a base from a square of 2 x 10. If the base should ever rot you just remove it and replace with another one, protecting the column. I have seen pressure treated begin to rot when in contact with concrete.

cdnNick 05-17-2012 06:09 PM

Here are some photos, the overhang is about 3 ft past the exterior wall, I measured it, it stops about a foot short of the center of the post. In my garage I can see 2 - 2x10 that are the outside edge of the porch and another set of 2 - 2x10 that should be the outside edge of the house.

Duckweather: how would you replace the base 2x10 if all the weight is pushing down on it? I'm assuming you would have to jack it up again? I'm trying to avoid having to do that again.

http://www.host-images.com/u/files/j...jweecp55pb.jpg
http://www.host-images.com/u/files/z...51wsymhah2.jpg
http://www.host-images.com/u/files/w...hgoydlsr0v.jpg

Ravenworks 05-17-2012 06:25 PM

I hope you realise what you are about to do requires a lot of know how and work.
I see temporary I-beams and shoring post being placed to spread out the load while the post is replaced.
If not done correctly you run the risk of losing your 2nd floor.

kwikfishron 05-17-2012 06:34 PM

Before this thread gets blown all out of proportion how about tearing off the two decorative wraps at the base so we can see the condition of the actual post.

EDIT: And peel some more paint while you're at it.

cdnNick 05-17-2012 07:47 PM

Quote:

Originally Posted by Ravenworks (Post 923586)
I hope you realise what you are about to do requires a lot of know how and work.
I see temporary I-beams and shoring post being placed to spread out the load while the post is replaced.
If not done correctly you run the risk of losing your 2nd floor.

Yes, we are aware of this. At this point we are trying to get enough info to determine what we should do. We will only move forward if we are comfortable with the plan. My father in-law would be coming up to help, we has a few jacks and we can make some temp support walls as well. If he wasn't 8 hours away we would be getting more help from him.

Quote:

Originally Posted by kwikfishron (Post 923590)
Before this thread gets blown all out of proportion how about tear off the two decorative wraps at the base so we can see the condition of the actual post.

EDIT: And peel some more paint while you're at it.

I was pick at the middle 2x8 with my finger and here is a picture of the results. I could push a screwdriver halfway through the wood. The middle piece is the worst, the 2 on either side of that are not as bad, but will soon be rotten and the 2 outside pieces are pretty good. The middle 2x8 is soft to the touch about 1.5 ft up from the base.

http://www.host-images.com/u/files/q...ppswhm9alp.jpg
http://www.host-images.com/u/files/r...emn6vald1v.jpg

forresth 05-17-2012 08:10 PM

Just use a pressure treated 6x6 (maybe elevated off the concrete slightly) and cover with vinyl or better looking wood.

Also find out were the roof is leaking or correct the porch slope. I don't buy that some snow in the winter caused that much rot that quick, even considering that is not pressure treated lumber. Leaky gutter maybe?

oh'mike 05-17-2012 08:31 PM

You might also want to remove some of the ventilated soffit from in front of the post--that will give you a view into the structure and the porch column attachment point--

The soffit is fairly easy to remove and replace---

It is possible--though unlikely---that the column is decorative and not supporting the structure above--only way to find out is to open up the soffit--(unless you have blue prints)

Duckweather 05-17-2012 10:41 PM

You only have to jack it up about 1/4" to replace it if the base is under the post, and that shouldn't be for 20 - 30 years with PT. I see in the pictures there are 2xs around the bottom, leaving a space around the top for water to get in between them and the post. If the end grain of the post is on the concrete it probably wicked the water up into the wood, or up between the 2xs, (capillary action). That's the reason for the base with post on top of it. If you want a sealer that keeps water out, Agent Orange sells an elastomeric caulking/ sealant. clear, gummy, and very aggressive. Alex I think the name is. If it doesn't say it's flammable it isn't the one. Lexcel at Ace, is another one. One of the only sealants that will stick to unpainted wood. usually a 50 year guaranty.

cdnNick 05-18-2012 08:13 AM

It's a long weekend here so I will try to rip off the decorative trim and the soffit so I can get a better look and more pictures. I found out from a friend of ours that her uncle frames houses in the area so hopefully we can get him to stop by and give us his opinion as well.


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