Building a new house near trees

[rockdude14]

So I'm working on building a new house on a quarter acre of land in the PNW. Its on a slope so the trees that are there I both like and stabilize the ground. Keeping them happy and alive is a important so taking them into account as I design is a priority. Or at the very least selectively choosing which trees to cut down.

I've read a lot of conflicting advice on the subject and I also have a unique situation with the house so even getting started on this subject has been tricky (hence why I'm here). The house is going to be built on pin piles, these are 2"-6" diameter steel pipes hammered down to bedrock than a small concrete pier that will tie it into the house. So no large poured foundation, digging, or even compacting the soil. While I will probably hit some roots, I shouldnt be cutting out like 25% like a traditional foundation. I'm hoping this both keeps the trees healthy and alive but also lets me build closer to them since my space isnt huge.

The trees I have are two sequias that are 96" and 60" in diameter (ya they are huge and I definitely dont want to either cut or kill them, especially if they fall on me). Then three firs that range from 24-36" in diameter. Which I'd love to keep all but I might need to compromise.

Any guidance on both the construction and how close you think I could build to these trees? Everything is in the design phase right now so its flexible. I would think the impact from the piles should be pretty minimal to the trees so hopefully I can get close but want to do this correctly.

Any thoughts or advice as I go through this process? Or any advice on what to look for in a local professional since this isnt a normal arborist job or just cutting down or pruning a tree?

Thanks

 

[Raintree]

It sounds like you're on the right track. Trees that size on a 1/4 ac., it's not about how close, it's how far away & still stay within the lot offsets.
Soil compaction and the crushing of the feeder root system during construction needs to be mitigated by extreme measures on mature trees.

 

[rockdude14]

Yep, its also a fairly narrow lot 60ft x 150ft and about half is a slope so not building there. Combined with offsets it makes everything fairly tight. As I'm drawing up plans any guidance on how far to stay away from these trees, is it like 5ft, or 15ft or 30ft? I know obviously more the better but there is a limit and if its too high, that means cutting them down which I dont want to do unless I have to. Any differences between the fir and the sequias? Right now its just sketching stuff up and seeing whats possible. Its just a big balance of compromises, staying farther away might mean a more complicated house design that costs more and is harder to build or less sq footage. I also dont need hard set distances but I do need a starting off point, because along with house design I need to do septic as well, as well as some other stuff. All of these areas effect everything else so everything kind of progresses together. The idea isnt to have everything perfect and completely defined at the beginning but by the time to break soil any changes are relatively small (not going oh **** I forgot about the trees or septic and everything needs to move 30ft but maybe 3ft).

 

[Skeans]

So I'm working on building a new house on a quarter acre of land in the PNW. Its on a slope so the trees that are there I both like and stabilize the ground. Keeping them happy and alive is a important so taking them into account as I design is a priority. Or at the very least selectively choosing which trees to cut down.

I've read a lot of conflicting advice on the subject and I also have a unique situation with the house so even getting started on this subject has been tricky (hence why I'm here). The house is going to be built on pin piles, these are 2"-6" diameter steel pipes hammered down to bedrock than a small concrete pier that will tie it into the house. So no large poured foundation, digging, or even compacting the soil. While I will probably hit some roots, I shouldnt be cutting out like 25% like a traditional foundation. I'm hoping this both keeps the trees healthy and alive but also lets me build closer to them since my space isnt huge.

The trees I have are two sequias that are 96" and 60" in diameter (ya they are huge and I definitely dont want to either cut or kill them, especially if they fall on me). Then three firs that range from 24-36" in diameter. Which I'd love to keep all but I might need to compromise.

Any guidance on both the construction and how close you think I could build to these trees? Everything is in the design phase right now so its flexible. I would think the impact from the piles should be pretty minimal to the trees so hopefully I can get close but want to do this correctly.

Any thoughts or advice as I go through this process? Or any advice on what to look for in a local professional since this isnt a normal arborist job or just cutting down or pruning a tree?

Thanks

My advice working and owning a larger amount of ground with a few of the species above is clear cut them anytime you cut a root it’s Compromised tree. Last thing you want is what happened to my brother’s in laws they had exactly what you described they had 4 40” Doug firs through the house 3 on top of all three rigs they owned as well.


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[ArtB]

Narrow 60 ft lot -- have the lots on either side of you been clear cut? If so, you now have a bigger problem with just 5 trees standing alone! You may need to harvest them and replant.

Pile to bedrock - where in PNW are you, in my area bedrock is over 60 ft down.

How long has it been since the narrow 60 ft lots were platted? If you 5 big trees have been standing alone for over 30 years you may be OK.

There ar 2 of my DFir on my 3 acre lot that have blown over in the wind (80 mph gusts) and bothe were on t;he edge of learings. You may have clearnings on all sides of ;you?

CLosest I put any structure to a big DFir was 16 feet.

 

[ArtB]

FWIW: Pin pilings in PNW

Cascadia subduction zone.

https://www.iitk.ac.in/nicee/wcee/article/13_95.pdf

Sounds as you already have your dream lot - more to worry about than the trees. Ask your builder, bank, insurance co, or local code folks their opinion on the article link above.

In own opinion, I'd never build on pin piles in PNW.

A Friend in Northridge CA had his house totaled in the Northridge Ca earthquake. He had earthquake insurance. Ins rebuilt his house, but thereafter was on a list of 'cannot get earthquake insurance'. The rebuild '2000 sq ft house' was on 25 or so 20 inch diameter reinforced concrete pilings, not spindly little tubes.

 

[rockdude14]

Thanks for all the advice so far. Here are some more pictures to get you an idea of whats there. The cabin is semi functional but because of the ground slowly moving over the years (70 of them to be exact) walls are a bit out of square, and anything done to it that doesn't include a new foundation will just induce more headaches in the future. Not to mention while its built well, it wouldnt be close to code today so adding or serious rehab would be much effort than its worth. The lot was platted in 1950, not sure the age of the trees but they are huge so I'm sure they've been here at least 30 years and probably a lot longer. Last owners had barely been to the property for the last 15+years.

The neighbors to the north and south, looking at google maps, never really had trees on the lots. However to the east there are a couple of lots full of massive trees and continuing up the slope its pretty heavily wooded.

The house to the south is on pin pilings (common technique for this very specific area) they went down about 50-60ft for each one (the bottom is defined as when they hammer in less than 1" per minute with a specific pile driving tool). This is pretty much my dream lot so I'm not looking to cut corners. I'm also an engineer so I know code can be wrong, even though you still have to follow it. Houses aren't really my expertise but thats a good article, I'll need to do some more research and see if there's a good way to deal with both hazards. Or come up with some ways to mitigate them.

Last picture is how much English Ivy had taken over the trees and my introduction to in tree work. Guessing I took down about 10-15klbs worth over the trees. So hopefully that will help keep me in their good graces.

 

[Ted Jenkins]

Rock I think you are very misinformed and wrong. You might be a fantastic person, but might have a hard time seeing twenty or thirty years into the future. What we have found is that trees near by can destroy foundations and lean or fall on houses. The only true precaution is to remove trees with fifty or a hundred feet of planned house. When I lived in Washington the most valueable properties were those with out trees. A very sure fire method to stablize a slope it to terrace the hill side and thus make the property more usable for other uses. I would believe this is not what you want to hear as you have envisioned a beautiful cottage amongst the trees. In my situation I had to go three to fourteen feet down to bedrock. My foundation was easy from some points of view, but removing tons upon tons of granite to allow for a house was quite a job. It however has not budged in many years of earthqakes or fires. Also what about the possibility of your lovely cottage burning to the ground. Here insureance companies do not want any major vegetation near the houses. Thanks

 

[ArtB]

Is that on the bluff above Puget Sound between Seattle and Everett (or between Olympia and Tacoma) above the Burlington Northern tracks, 'typical' million dollar view lot at today's real estate market.

If so, and if the previous owners did not put in good drainfields on the slope with pipes down to the bottom of the hill, that is your first priority.

You could also contact Burlington Northern for the landslides studies they have done along the entire Tacoma to Everett route.

I would stay 20 foot from the trees, and stop and reassess excavation if you start hitting small root systems. (after assessing the drainage and landslide risks)

 

[old CB]

I just scanned this quickly, so cannot offer a comprehensive response. But it sounds like you have a situation that no one but a local can address with certainty. Someone who has lived in your area for a long long time is your best bet for an answer on this.

Local geography can be complex. And you describe some challenging aspects.

Your realtor who sold the lot will be useless.

But ask around. Start at the local hardware store. Talk to people at the breakfast cafe. You need to know how trees behave in your neighborhood, and there are a few old-timers who can advise you. Be prepared to buy a round at a local bar.

 

[ArtB]

Brian: (I'm assuming you are Brian from Snohomish county property records -- I found your lot easily as the view of Whidbey Is. was familiar from your photos) )

I think I'll be going right past your property in 2 weeks on the train so can get a 'quick' look from the train tracks.
I need to go to company offices in Harbor Pointe every few months, will even drive by if I happen to be in that area in the next few months.

There are a lot of conflicting views on ivy on trees. I usually cut it off. My next door neighbor - who was retired head of King County parks - ws of the opinion that any risk from the ivy was offset by the lush appearance.
You might want to start a separate thread on advise about cutting the ivy and see what the pros say.

 

[hseII]

Brian: (I'm assuming you are Brian from Snohomish county property records -- I found your lot easily as the view of Whidbey Is. was familiar from your photos) )

I think I'll be going right past your property in 2 weeks on the train so can get a 'quick' look from the train tracks.
I need to go to company offices in Harbor Pointe every few months, will even drive by if I happen to be in that area in the next few months.

There are a lot of conflicting views on ivy on trees. I usually cut it off. My next door neighbor - who was retired head of King County parks - ws of the opinion that any risk from the ivy was offset by the lush appearance.
You might want to start a separate thread on advise about cutting the ivy and see what the pros say.

Ivey get its nutrients from the root systems in the ground & only sticks to the bark but doesn’t typically cause damage to the tree.

However,
It has the ability to mask defects in the tree which can lead to failures.

It is my opinion that Ivey should be removed from trees near dwellings so the trees’ health can be routinely assessed.

Cut the Ivey all the way around the tree with a hand saw at ground level & at about 5’ above ground level. Remove this circumferential section being sure not to damage the tree. This will kill what’s in the tree.

If you do this during a “dry season” this will typically kill the roots due to lack of nutrients & sunlight.

We had good success with this method last year but we don’t live in the PNW.

So if you are still in need of removing the roots after the circumferential section has been removed, rent a 185cfm air compressor & air spade the root system to remove.

Don’t Try to Grind it with a stump grinder: tree root damage will occur.


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