Architecture - aging post and beam construction

I had this over in carpentry for a day, couldn't get a nibble, so thought I'd try over here...

We have a sunroom, built on 27, 6''x6'' p.t. piers 16 years ago. The piers are placed on concrete footings and concrete is 2' deep, below the frost line. Later, we added a deck around this room, so now it's difficult to know what condition those piers are in, but am going to attempt to scuttle under there for a look. If I find the posts are deteriorating, what would be my course of action?

The roof to this sunroom is tied into the main roof of the house, and the room is a completely finished living space with a ceramic tile floor. I don't think there's enough room to get under there to dig, although I could remove the deck boards to do so.

Thanks for any advice or ideas. Connie

Connie,
It sounds as though the piers are pretreated lumber since they are 16 years old and withstood any weathering til now. Had the posts not been installed correctly and be subjected to constant ground moisture contact, There would, by now, be some obvious effect to the wood. It sounds as though you're looking for a problem that doesn't exist.
Let's carry this one step further though! Again, I'm presuming (I think safely) that the wood is treated lumber. IF, after this long of a period, the wood should start being effected by moisture, a simple garden pump sprayer can be used to get into the tight areas to saturate the posts with wood sealant.
Frankly, on a worst case senario, if the wood starts to decompose after all these years it'll take decades before any big problem would cause a major structual concern presuming there is no big change with the current exposure.

CD

Thanks so much for your response. I actually feel much better now that I've had confirmation. I was so concerned that I had posted this in exterior forum. Tscarborough also stated that I was probably worrying needlessly.

I appreciate it so much and that's a clever idea about the pump sprayer.

Have a great day!

Connie

The ground you are in, means a lot. If ground underneath is subject to freezing, heave can occur, therefore, simply stacking blocks, (as an easy fix) under there, could cause structural uneveneness, cracked tiles, raise roof at where it ties in at the house, etc.

Were footings poured and then the concrete just rests on the footings?, and then dirt, gravel or sand filled in around the posts?

There is this claim floating around out there that says to backfill with pea gravel, as the theory goes that during frost heave the gravel acts like ball bearings and the ground around the posts can rise up without the post lifting, but I do not buy into that theory (at least for outside posts subject to water and snowmelt). If memory serves me, I tried it on a garage, some years back, where the pilings are about 4-6 feet in the ground ( I live in REAL cold country),and the posts lifted anyway. MY theory: the ground around the pea gravel and frozen water scrunches the gravel into the wood and actually grabs hold, as opposed to allowing the post to slip as it should, in THEIR theory. Maybe on interior pilings that stay dry, their theory holds up better.

When you crawl under there, tap the same way, at the same location, with a hammer, down low on each post, to listen to see if the post goes 'ringgggg' (good), or a dull 'thunk' (not god).

Hi ecman,

The posts were backfilled with the same clay soil we dug out. That was according to code at the time, I don't know if the standard has changed. We're in Virginia, so there's plenty of freeze/thaw here. It's pretty well graded so that the water runs away from the structure, and it never gets wet in the middle, just around the perimeter.

I am considering tearing down the deck in a year or two- just tired of the maintenance. I think what I'm trying to get at here is this:

If those posts are deteriorating, is it possible to get a poured concrete foundation under it?

If those posts are deteriorating, is it possible to get a poured concrete foundation under it?

Almost anything is possible if you are willing to pay. Getting under there sounds like the issue.

If you are going to do a tear-down in a couple years, and for some reason fear the worst in the interim, you may want to just shore up next to the posts with concrete blocks on pads, where you think might need it the most.

Is there a lot of frost heave around your property, or not? That might make you think twice about simple blocking, as suggested? I have seen areas near where I live where it is not that bad, due to sandy soil and drainage. But right where I live (sand, but clay under that, in a swamp, basically) it can heave like 4 inches, even more - a terrible dilemna for add-ons next to existing, unless you do things just right.

Are you going to crawl under there and maybe tap against those posts?

I don't think I'll be able to just wait and see- I'll have to do the commando crawl and drag that hammer with me. I know what rotten wood sounds like, but I usually just take a screwdriver to see if it's "punky".

We have lots of heave- one section of my driveway was added at a later date. In the winter, sometimes the concrete on the left of the expansion joint is two inches higher than the concrete on the right.

I probably won't be getting under there for a while. We had three inches of rain yesterday and are expecting more tomorrow and Saturday.

Let us know what you find out, under there. Be sure to let someone know you are going under there.

Thanks, ecman...that's very kind of you. Have a super day!

It WILL be, after I leave soon and come back with my Moo Moo Gai Pan Chinese meal.

I think about letting people know because I have had to crawl under trailers in way below zero temps and I have thought how it would not be good if you got a heart attack or something under there, and nobody knew where you were and later found you frozen like a board. On another recent occassion I pondered crawling in the attic space of a strip mall through metal joists/trusses to get at a handling units duct, and thought better of it, and instead moved to a location below and accessed from that point. I had visions of paramedics trying to figure how to get me out from up there from all the jail-like bars of metal. And the other night I had to lock down this building, after everyone left in the dark, and nobody was around for blocks, and I had to walk out along the building on glare ice to shut a door, and had those same thoughts.

That's good advice for all DIYers. (But I never thought of things like that when I was 25!)