Long shot ???: SIP Panel home construction - remediation and repair of rotting due to weather & mice

Hi everyone! While this is my first post here, I've been a regular over the last 3 years - brought in by the @mazdeuce story, and stuck around getting inspiration from all the creative builds, both auto and otherwise.

This post is a total longshot, but if there's ever been a community of capable, intelligent, expert ingenuity when it comes to building E36 M3 and fixing E36 M3, this is it and I've never seen anything better.

So here goes, hoping perhaps someone sees this and is able to shoot some advice my way...

My wife and I are first-time home purchasers, just moved into our place about 2 months ago in Livingston, Montana. It's built in 1996 and the foundation and structural components of our home is a combination of SIP Panels and ICF.

Before purchase, inspections went well and inspector was generally impressed with the construction quality and insulation characteristics of home. Living in the home for a month with radiant heat has been extremely comfortable as winter has arrived.  We love the house and the town and already engaging as much as we can in the community despite pandemic.

However, one little fly in the ointment...

I'm currently a bit overwhelmed having discovered a non-trivial SIP panel issue, and seeking any advice from experts who can guide me towards ideal solution.

While removing the basement carpet and baseboards in preparation of replacing with new flooring, I discovered a spot behind one the baseboards where cold air was blowing into the home.

After further investigation, tearing out part of the back deck (that looked in good shape from above - pic 1) exposed the completely rotted bottom half of exterior 2x12 wood base panelling (pic 2). Pulling off these rotted I discovered (pic 3) a completely rotted out lower foot of OSB on the sip panel, plus a network of mice tunnels through the EPS Foam, leading directly to the interior corner of the house where I felt the cool air - mystery solved...now to figure out how to fix it??

Pic 1 (Deck before being torn out):

Pic 2 (Deck is gone, rotted lower side panels remain):

Pic 3: Side panels off...OSB & sill plate deteriorated, network of tunnels through the EPS foam (Yikes!)

I'm assuming the rot occurred hidden out of sight for years due to snow buildup and melt in that inner corner, and lack of proper drainage underneath the deck. The mice making it their passage way into the walls didn't help things.

Of course part of solution is having some mice pros come out to determine extent of current mice infestation and resolve, which sucks, but I've experienced this before and can handle it.

My bigger concern is the structural integrity of the SIP and bottom sill plate and how to properly remediate/repair?

The base (sill) wood (2x6 I think) under the OSB is also largely rotted from the outside - I've scraped out at least 1-2 inches inward from outside before hitting solid wood. Also rotted as are the lower parts of the adjacent vertical wood beams to the right (outer corner end) of the damaged OSB.

Both the neighboring SIP panels are in better shape. The outer corner panel just has a tiny bit of rot maybe 4 square inches in its lower left corner. The inner corner panel (also hidden behind part of the deck in above pic) has rot on the lower external OSB ranging from 1-10 inches high, but underlying EPS is fine. It is also still slightly rotted on its sill plate but not as bad as the one with the mice holes.

The inner corner interior SIP connection appears to be fully secured via spray foam adhesive from the inside, with just the mouse portal coming in through the EPS on the bad SIP panel. Here's a pic from the inside (as we pulled off trim and paneling, we found this corridor behind the better of the 2 SIP Panels, with a classic framed drywall on other side 6 inches away.  This corridor had 2 pieces of insulation sitting in the bottom of it, completely disgusting - we've cleaned it as best we can - Possible there was once more insulation that was torn out as part of earlier infestation/water damage?). There are 2 entry points for the mice from the short edge of the affected sip panel (immediate on left side at beginning of corridor), one at floor level and one 4 feet up.  The tunnels might be extensive up and down...we're hoping the rodent guys have cameras and we can deduce just how compromised it is. 

So yea what started as a flooring replacement project has quickly turned beyond my paygrade. The handyman I work with who is more than capable of patching it up (steel wool and spray foam in the mice tunnels, cut out OSB rot and re-adhesive replacement OSB in it's place, weather wrap, replace siding). But he recommended I consult with some experts before just putting a bandaid on it...especially due to concern of structural integrity due to missing foam and rotted OSB / sill plate.

I'm trying to reach out to local contractors but everyone is swamped and not sure any of them even have SIP expertise. Spoke on phone to an employee at the local manufacturer of SIP Panels in Belgrade, MT (https://bigskyrcontrol.com/), and he was helpful with outlining remediation tips in previous paragraph, but he was not a structural engineer and couldn't provide advice on possible load bearing issues. I watched a ton of videos on removing rot from sill boards in regular construction, which seems like quite a beast on it's own, jacking up the house and everything, but don't even know if that's possible with SIPs? I have another call scheduled with a local reputable restoration company this afternoon.

Any pro-tips on what techniques we might try or contacts who I might reach out to to ensure we handle this properly would be greatly appreciated.

Thank you all so much. (And special thanks to mazdeuce - it's all his fault I'm here making this post)

-Trevor

I'm not seeing any evidence of building wrap or flashing in your photos, which is deeply concerning.  If this was my project I'd foam the voids then flash it well with galvanized steel to prevent further rodent intrusion.

How many SIP panels are rotten across the bottom?

See if you can't find plans for the house. That might mean calling up the original owner, or tracking down the original builder. 

That'll save a ton of time with a structural engineer. 

Paging SVREX

nderwater said:

I'm not seeing any evidence of building wrap or flashing in your photos, which is deeply concerning.  If this was my project I'd foam the voids and flash it well with galvanized steel to prevent further rodent intrusion.

I'm no expert but that was my thought too. I mean, a lot of homes out there aren't flashed at the sills. Mice can get in that way. But with a traditional stud built home, they either go through the interior wall, or they have to go through the studs to move around in the house. 

With the insulation being the only barrier once they go through the external plywood, they can move around quite freely. I guess the benefit here is you could rip off that affected plywood, respray the foam "channels" our little friends have made, and cover it back up with a rodent resistant sheeting or flashing. 

Around here, all sellers are required to provide one year of a home warranty. There are different levels, but you should look into that and just pay your little deductible and sit back while a professional fixes it

I've never used SIP or built with it, mostly because I hate foam as a building material. You can guess my thoughts on ICF too 

As a concrete guy though I can tell you that the rot is caused by the concrete only being what looks like 2 inches above grade. That's way way too little and the OSB will pick up any water close to it with that little clearence.  You nay have that problem literally everywhere .

pheller said:

Paging SVREX

Hi there! Haha!!

In reply to tgribbs :

Welcome aboard!

Really good summary!

In reply to tgribbs :

Simple summary...

Your repairman is right. You need an expert. No one on this website (or on the internet) is an expert. 
 

Neither are local contractors. 
 

The expert you need is a structural engineer familiar with SIPs construction. 
 

(slightly longer response coming with my opinions)

SIPs panels get there strength from the overall combination of the bond between the outer layers of plywood, and the insulating core and adhesive.  You are not just replacing components (like OSB or spray foam). You have lost the strength of the overall engineered bond of the components.

If you can identify the manufacturer of the SIPs panels, they may be able to give you free engineering to design a repair.  I'd check with the local building department to find the original plans submitted. They should show the builder (who probably can't help you), and the manufacturer.

If you can't find the original manufacturer, you will be stuck paying an engineer for a design. No contractor or carpenter can design the repair for you. (Although they can execute it)

Not only are your panels designed with an overall integrity of the panel components working together, but your entire building has a similar approach.   Each panel depends on the panel next to it.  
 

You said only 1 panel had bad rot, and the adjacent panels are ok. That's probably good news.  If you have essentially a 4' long structural failure, it's one that a repair should be able to be designed for.  But again, that's an engineer's call.

The other observations about water proofing and proximity to the ground are both very valid.  You may determine this is worth removing the 1x12 rim board to inspect. A consultation with the engineer should include discussion of this.  It's possible there is a low impact solution- like a commercial grade water proofing to prevent further deterioration. Metal flashing by itself is probably not the solution- still too close to the ground.  Don't overlook this. It is probably a minimal problem now, but could be a disaster later.

Excellent job recognizing both the inherent value of the SIPs, and the potential structural problem that might need expert assistance.

Again, welcome aboard, and good luck!!

In reply to nderwater :

Yea there's literally no wrap that I've found in that corner. Just the board and batten paneling with fair (not great) application of caulk filling all the cracks.  It's possible this is the case around the whole house and might need to be a summer project to rectify for long term health.  

Some missing flashing flashing on the sides of the house was noted by our inspection and fixed by the seller, but everything under the back porch went unnoticed until now.  I've done my best to crane my neck and look between the planks to see evidence of failure, and it looks sound the rest of the way around...even pulled off one of the 2x12s to check and OSB was in fine shape, but yes should be flashed for sure. 

In reply to jfryjfry (FS) :

Good call, will start chasing that as well.

In reply to Antihero (Forum Supporter) :

Makes total sense...The good news is the concrete/foam foundation is much higher above grade literally everywhere except this one corner where ground was raised up was hidden under the deck.  There will need to be further investigation around the whole home, but I think this spot was the only major violator of that principle.

In reply to SVreX (Forum Supporter) :

Looks like others here knew you were the guy!

LOL on my original post referring to experts about 10 times...I guess I just hold everyone here in such high regard for their collaborative effort in helping each other solve complicated issues and sharing detailed steps along the process.  I'm sure there are some miserable parts of the forum as well but I've managed to stay in the elevated regions, and looks like I've found that group with my post.  I knew I had to come in swinging with a proper summary (thanks for the compliment) to meet the expected standard and get these types of replies.

I've just taken a video as well to better explain the layout of the interior and exterior of the house, in case it helps paint a bigger picture for anyone interested..(sorry about vertical video, forgot I'd be uploading to youtube). 

https://youtu.be/EHEabHg5Igo

Your explanation of the SIP integrity is exactly why I started down this wormhole of concern and indeed if multiple panels were breached I'd be even more worried, but it does appear the major internal issues are limited to that one corner panel (better shown in video).  After speaking with the mice guy just now, I'm sure there are probably attempts at mice tunnels in other parts of the structure as they've clearly been in here for many years, and there's foam literally everywhere in both SIP and ICF. Plus dozens of potential entry spots all around the house, but tearing everything apart to try and find them is a task I'd like to avoid.

We are beginning external and internal mice remediation asap, so I should be able to know we are not allowing any comfortable neighborhood for the guys currently inside, will plan on at least temporary patching up the visible holes (and pull off board and batten paneling above compromised sip to look for more evidence.

Will simultaneously start hunting down builder and manufacturer to see what I can find...I did contact a local architectural company yesterday looking for structural engineers in the area, and they recommended I call the Big Sky R Control manufacturers that I referenced in original post (https://bigskyrcontrol.com/).  Will go back into that pathway as well before starting any repair purely based on contractor recommendations.

Thanks a ton

You taught me something. 
 

I was unaware that SIPs were so desirable as rodent condos.  That will change the way I use them, install flashing, and protect them. 

For some reason I was blocked out when this first appeared. To be clear my house was constructed around ICF's and Sips.  
I took great care to prevent mice problems.  First I choose any SIP or ICF I used to have  boron which has been proven to cause insects or mice to die after eating  enough. Thus a limit to damage.   
 However this fall I found a short coming to that problem. Woodpeckers don't injest  the foam they peck through it. Trying to hear insect movement. It's my fault I made my exterior trim out of hardwood and stone or stucco. My foundation is protected 2 feet down with Granite 2 inches thick.  Pecking gets them no where.  
The roof is soft. Cedar shakes then cedar breather with only the roof sealant to dig throughout get to the roof SIP. 
 The problem is they start small holes that other scavengers take advantage of. In my case squirrels. 27/12 pitch is appealing to them. I've spotted a hole one created ( currently inactive) but I will drop some squirrel deterrent    that I know works 

OK what does this mean for you? 
    replacing a panel isn't rocket science. You can spend money having "experts" tell you what you already know.  if you find it's two panels again it's not a big deal.   Panels aren't that expensive and if your guy is good he can reuse the exterior parts pretty well and sheet rock isn't expensive on the inside. 
 

In reply to frenchyd :

I definitely appreciate the insight.  For past 48 hours I've been wavering between, "Oh this is no big deal the house has been here 25 years and it's still standing...and...holy berkeley the entire structural integrity of the property is at risk!"  So yea felt it responsible to prepare for worst case scenario and hope for the best...I'm sure this is also because i'm only 6 weeks into owning my first home. I'm sure I'd give it a lot less concern if it weren't my first rodeo.  But it legit is my first rodeo!

Well...

"holy berkeley the entire structural integrity of the property is at risk!"

Is DEFINITELY not the case. 
 

It's a repair. It's fixable. It's likely you can do it. You just need an engineer's input first. 
 

You've handled it perfectly so far. Even for a newbie! 

BTW...

Its also not a crisis.  I discovered a pretty significant termite infestation in my house recently.  Let it sit, then got it fixed 6 or 8 weeks later, or something like that. 
 

Don't rush it and make bad decisions. 
 

If a contractor says "OMG, your house is gonna fall in if we don't get started fixing this RIGHT NOW"...

...that guy is full of E36 M3. Pass him by and patiently wait for the next guy. 
 

All will be fine.  Just take one step at a time. 

tgribbs said:

In reply to frenchyd :

I definitely appreciate the insight.  For past 48 hours I've been wavering between, "Oh this is no big deal the house has been here 25 years and it's still standing...and...holy berkeley the entire structural integrity of the property is at risk!"  So yea felt it responsible to prepare for worst case scenario and hope for the best...I'm sure this is also because i'm only 6 weeks into owning my first home. I'm sure I'd give it a lot less concern if it weren't my first rodeo.  But it legit is my first rodeo!

I guess I missed the part of owning it for only 6 weeks, sorry but you probably have recourse to the damage.  Did you say someone had been in there to repair it previously?  
    If so you really do have a legitimate claim against the prior owners. It might be time you talk to an attorney.    Bring your pictures and the result of a survey to an attorney. Remember your first consultation is free with no obligation but don't expect straight simple answers either. 
     A good attorney will refer you to someone who typically handles exactly that sort of case.   A lousy one will claim lots of things  and ask for a fee up front. There are a lot of underemployed attorney's surviving from law suit to lawsuit. Not really current on their student loans decades after college. 
        You can't possibly know which are which but you can get references."Who besides yourself handles these cases"  is a question you need to ask until you start getting answers you feel comfortable with. 
 

Having gone all that way down that road, the previous owner may be a decent sort and voluntarily help you without threat of legal action.  Or might need a prod from an attorney. 
Just get costs up front so you can see if the cost of legal support is greater than the cost of correction in the first place.  Whatever don't let anger, ego, or fear  force you into making a foolish decision. 

In reply to SVreX (Forum Supporter) :

Yea I think it took me a full 48 hours to come to the non-crisis realization.  It's definitely not a fun sight to come across when we got the panel off and certainly felt like a crisis in the moment!

There were also a bit of stress thinking about the timing and potential re-scheduling of a lot of related (mostly aesthetic) projects that had a bunch of inertia built up. We had been planning on taking time over the holiday weekends coming up. (painting, floor install, furniture purchases, etc)...so getting a better understanding of how much repair is going to be needed and if we should wait on everything else so we don't have to re-do anything twice - is probably a blessing in disguise.

But as always, getting up early, having some quiet time, looking out at the stars, walking the dog while catching the tremendous sunrise helps put live back in perspective.  Definitely won't let ego or stress make these decisions.

If I learned anything from this forum (and especially the mazduce classic that brought me in)...patience,coffee and a little bit of help from random weirdos on the internet can solve anything.

In reply to tgribbs :

Excellent!

Regarding legal action... I know some people have suggested this. I can't think of a bigger waste of time.  This was concealed damage. Even a home inspector didn't not catch it.  You'd have to prove the previous owner knowingly concealed something- it's highly unlikely they knew anything.

Looks to me like they acted in good faith, and did not conceal known issues.

If your home inspection is warranted (unlikely), you could file a claim against that.

You may have an insurance claim, but you definitely do not have a legal claim against the previous owner.  Don't waste your energy.

I always try to make lemonade when handed lemons.  Is this damaged panel in a location that a new door could go? 

One of my dad's buildings had a Christian book store in it and the patrons weren't the best drivers. One lady put her car in drive, looked over her shoulder to back up and went through a block wall in front of her.  My dad looked at all the broken bricks and decided we could get enough full and half bricks out of the pile to fill in most of the hole. The building got a new people door to the stairwell she ended up in.