Duplex wet crawl space - need opinions/feedback

10 Replies

Hey folks,

Just closed on my second duplex last week!  This one needs some work but the numbers look good.   My particular question today is regarding a wet crawl space.

I'm north of Seattle so this is a wet climate, but the summers are dry.  The inspector noted some standing water in spots and mud in the crawl space on top of the existing vapor barrier.  In tandem with this, the existing gutter system is completely clogged and the ones that are not drain straight next to the foundation.  The lot is completely flat as is the surrounding area, and the yard in general is saturated (not uncommon at this time of year).

My initial reaction is that I should fix the gutters and get them draining away from the foundation, let things dry out and then evaluate the situation further next rainy season.  At present there is no damage to the joists or any really visible mold growth, so my gut is telling this is a "wettest time of the year combined with no working gutters" situation.

A contributing element to this is that one side is vacant currently.  I'm doing work in that unit over the next 2-3 weeks.   Access to the crawl spaces is through a small hatch in the coat closet, so doing crawl space remediation without a tenant to deal with might make sense.

I'm wondering how others might proceed.    I don't like the idea of moisture down there at all, but I don't want to overspend under the house when the gutter situation may resolve it.

Hi Jeremy

Congrats on the acquisition. I would fix the drains asap. Look for the simple and obvious first like easy entry through the foundation (a crack) during excessive rain, pooling ect. If you haven't already done so enter the crawl space and have all of the sinks toilets laundry ect. turned on and see if you have  drain pipe leaks. Be sure that you turn on the shower side of tub combo as sometimes the pipe going up to the showerhead will leak once it is activated. I would go look at the drainage when you are having a lot of rain. Hope that is helpful.



Thanks for the feedback.  I was already down there doing some duct work repair, so it's a great idea to turn on all the water sources and check the drains.     Appreciate it.


I would fix the water issue and drainage ASAP. I would start with the guttes. Water can cause a lot of damage fast. 

So plumbing is probably piggy backed together, I would check under bathrooms & kitchens. Turn on water have someone with flash light check.

Your duplex access sounds just like ours.  We normally are going down to excavate dead cats, not water.  :)  The neighborhood has a feral cat population and my tenants keep putting out milk for them and compromising our screening barriers.  

I wouldn't go overboard, because the soils seem very saturated right now and the gutters may resolve it, but it will never be this easy to get access, so if you are on the fence, do the work now.

I have a similar issue on my duplex. We also have very saturated ground from about April to early June (from the winter snow melting). Is your vapor barrier well sealed against the foundation walls? Check for past ground water intrusion along the footers and wall as I find it unlikely there were pipe leaks that caused mud to form above the vapor barrier. Ground water could have carried sediment above the vapor barrier if the water table was high enough and the barrier not well sealed. If this is the case, the answer might be to install a sump pump. Also let me recommend that if you do go the sump pump route, install it in the dry season as it is my experience that digging a new pit below the water table is ridiculously complicated.

Thanks everyone for the great feedback.  I took a look this evening and don't see any signs of leaking pipes.   Going to deal with the gutter situation and see what impact that has and then go from there.

Jeremy, I had the same problem in my home; bad smells, water standing, etc.  This is always a step by step procedure.  Just like the others said; fix gutters, drain away from foundation.  Any ground near foundation that slopes towards the house; re-grade.  I had further water intrusion and installed 4" perforated piping along the footings, which was graded to drain into a sump basin under the house.  I wired in an electrical box (outdoor GFCI) and connected a sump pump. We re-installed thicker water barrier material from wall to wall.   The remote hygrometer reported less than 45% moisture.

It beats complaints from others about a "musty or moldy" smell. 

Something to consider is a Turtl box for outdoor access to crawl spaces (lockable).

We installed one and do not regret them, allows plumbers access to crawl space without going through tenants home.

Good luck, -J.

just getting the water to shed away from the house would go a long way. you might get some of those corrugated downspout extensions to help get the water away. Get the long black ones that look like pipe. The green ones are junk.

if you want some brownie points with your locality, send the gutter water to a rain garden

I like the idea of added external crawlspace access for sure.

That's a good suggestion Ryan.   Our local water authority sells rain barrel kits at cost and encourages their use.

I was thinking that a rain barrel connected to a soaker hose that discharges away from the house could be a good way to handle larger brief amounts of rain.   The goal here wouldn't be to save water for future use but slow the amount of water entering the yard during heavy rains near the home.

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