Service Life of Wood Framed Houses? 1

[Logan82]

Hi!

I am looking to buy a house. In the area where I am browsing, the houses all have approximately 60 years since their construction. They are built with a wooden frame.

I was wondering about the service life of wooden framed houses. In 35 years when I will sell the house, will the buyers need to have the wood structure or its foundation replaced or any other major component for them to use it? At which point will the house need to be replaced as a whole?

I am asking because for some civil structures such as some bridges, the service life is 60 years. You can sometimes add maybe 30 years of service life if you perform major repairs. But after that some bridges need to be replaced.

 

[rb1957]

It's probably limited by maintenance, and if problems (water, bugs) are allowed to go unnoticed.

another day in paradise, or is paradise one day closer ?

 

[dik]

Water and wood destroying critters are the main problem. There are wood structures in Nepal that are approx 1000 years old.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[SnTMan]

There are wood buildings in the US that are hundreds of years old. In contrast there are structures using newer tech that will never last that long.

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[rb1957]

a reference to a building in Florida ?

another day in paradise, or is paradise one day closer ?

 

[EdStainless]

Look for water or bug damage, foundation issues (settling), and is there any sagging in rafters or joists?
If the house is still close to square and level then regular maintenance will keep you fine.
My grandfather's house was built in 1840 and other than a few wonky floors (that have been that way at least since 1940) it is still very solid.
On thing to keep in mind is has this area become wetter or dryer than it was in the past? In didn't used to think about this but in some areas rising or falling water tables are casure real foundation issues.

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[IRstuff]

To some degree, older houses might be more robust; my parents' house was built in 1926, and nary a 2x4 to be found anywhere; the smallest stud was 4x4.

On the flip side, the house had aluminum electrical wiring "upgrades" somewhere in-between.

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[phamENG]

And while historic houses tend to be a bit more robust in terms of the member sizes - an apparent abundance of material made it possible along with the milling technology available at the time - they lack the same robustness when it comes to connections. I remember a couple years ago a hurricane came through south of here...a giant, stately home that had stood (and had been meticulously maintained by the historical society, I believe) for about 200 years slid right off its foundation and crumbled into a pile of very large, beautiful, and stately rubble.

A lot of details used in the past are horrible for houses - pine sills sitting on clay brick foundation walls - and their only saving grace is the ridiculous sizes of the members - those pine sills are often 8 to 10 inches thick. Those that have survived this long are now facing outrageously expensive repairs to correct these issues.

The trouble with new technology is that it's untested. A lot of it is good, but we don't know with certainty how long it will last. A lot of that can be solved by 1) not being on the very cutting edge and 2) designing to make replacement and repair easier. I love historic structures - it's one of my 'niche' practice areas - but for my own home I'd take a modern house built by a competent contractor and in a classic style rather than buy a 100 or 200 year old house. A tract home? I'd probably pass on that and take the historic house if it's been well maintained and undergo the necessary structural retrofits.

 

[XR250]

I think any house constructed with a proper foundation, without glued materials (aka Plywood or I-joists) and with proper moisture and insect management should last almost forever. I imagine the wood would possibly outlast the concrete.

 

[phamENG]

XR - while I'm also skeptical of the longevity of I joists (creep in glue joints, embrittlement of the glue over time, etc.), why plywood? Generally speaking, it's doing most of its work in plane and the loads are fairly short term (if you ignore p-delta/stability loads, of course). I can see roof sheathing requiring replacement due to elevated attic temperatures degrading the glue, and possibly exterior sheathing due to radiant heating from the sun. Fortunately those are generally in "accessible" locations and can be repaired while finishes are being repaired or replaced. But what about interior sub-flooring if properly insulated and kept dry?

Does your doubt extend to LVLs as well?

 

[XR250]

can see roof sheathing requiring replacement due to elevated attic temperatures degrading the glue, and possibly exterior sheathing due to radiant heating from the su

Exactly. Yes, LVL's too. We have no idea how long the glue will last.
Steel, concrete, masonry, dimensional lumber and diagonal sheathing FTW!

 

[JoshPlumSE]

I was wondering about the service life of wooden framed houses. In 35 years when I will sell the house, will the buyers need to have the wood structure or its foundation replaced or any other major component for them to use it? At which point will the house need to be replaced as a whole?

My house is just shy of 50 years old: I've lived in it for 20 years. It's wood framed and has had it's share of problems. Let me elaborate:
1) Settlement under an addition that was done when the house was about 10 years old. We replaced some drywall and add some leveling topping to the slab in the worst areas and the problem is essentially unnoticeable.

2) Drainage: Twice the house has experienced minor flooding during a heavy rain. This was due to a poorly sloped back yard patio that was added many years before we moved in. We ripped up that patio and replace it with one that was properly sloped away from the house. Only real damage was that we had to rip up the carpeting in these areas.

3) Mold: That same addition that caused the settlement added some areas to the roof that don't drain well which led to some mold in our garage. It's an on-going maintenance issue. We just have to make sure that leaves and debris don't accumulate on the roof in this area. If we take care of it, the drainage is fine.

4) Termites: We have to tent for termites / bugs and replace some eave boards and such. Honestly, if you're paying attention, it's not difficult to spot.
The house was tented when it bought it 20 years ago and we tented it again this last year. So, you have to keep an eye on it, but it's not a huge problem.

In summary, most of the issues were related to poor work that was done to the house AFTER the initial construction, but before we bought it. Once we corrected that, the issues are merely normal maintenance issues. I expect the house to survive nicely for another 50 years or so.

 

[JoshPlumSE]

Oh, we also replaced almost all of our windows and some of our doors. But, that was because we wanted more energy efficient ones as the house used to get really hot. Now that we've upgraded those windows, our house is very comfortable most of the year..... Well, we added Air Conditioning as well. But, the windows made a HUGE difference.

 

[CrabbyT]

As long as the house has been well-maintained, it can last an incredibly long time.

My boss let me take a look at his family's barn (over 100 years old) and he asked me why I thought it's stood up so well. I reckoned the paint had a lot to do with it. They really kept up with it. Not to mention, the floor joists above the basement are literally trees cut in half lengthwise.

 

[Tomfh]

If the wood is kept dry and in good condition then hundreds of years.

 

[LittleInch]

I would say a lot of the longevity or not is dependant on what is providing the water resistance in the roof and the external cladding.

Brick? timber? Tiles? Fabric (tarpaulin) etc.

Unless you get rising ground water the bottom of the frame should be ok and keep all the bugs out.

The thing you can't check is the quality of the construction when it was built.

The real issue is whether you can get insurance cover for wet or dry rot or termite damage. That's the big risk.

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[Logan82]

Thank you all, you gave me interesting fact on the subject of wood framed houses. I must say that I am surprised that their service life appears to be sometimes longer than the typical lifespan of bridges.

 

[phamENG]

Consider the service conditions. A house has relatively benign conditions - if you maintain the building envelope. If you let water in, it won't last 5 years. A bridge is typically exposed to the elements constantly for decades. Except covered bridges, and some of those have been around for a couple hundred years.

 

[IRstuff]

There was an apocryphal story that the painters for the Golden Gate Bridge would start painting at one end and by the time they got to the other end, it was time to start painting again.

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[LittleInch]

The Forth railway bridge got there first...

https://library.panos.co.uk/features/stories/painting-the-forth-bridge.html#0_00148569

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.