Rainwater Management: Gutters & Downspouts

[Bobonli]

I’m hoping some homeowners with more experience than I can help. What are your thoughts about burying downspouts underground in an effort to get water away from your foundation?

(TLDR): I have a home that was built in 1954. Cinder block foundation. Old cinder blocks, the type that crumble over time! The people that built my development also cleverly pitched the yards toward the foundations. Another architectural feature was running the gutters to downspouts that ran down the side of the building and into a clay pipe next to the foundation, the pipe eventually leading out to a cistern in the middle of the lawn. Over time, of course, the clay crumbled and water just collects next to the foundation and weeps thru the cinder block. When I bought the house 11 years ago the owners admitted there was a water issue, and they installed a French drain in the basement, the water is pumped out through a sump pump. They also sprayed some super-thick mold retardant paint over the cinder block to conceal the leaks. Over time that paint has worn/broken off, because the water handling problem is still present: every time it rains water comes down the spouts, hits the lawn and flows back toward the house. I’ve tried those accordion extensions and the most I get is 5-6 feet away from the house but it’s not enough to prevent the ground from getting saturated and leaking through the foundation. Plus my landscaper is always removing or mowing over the extensions, usually right before a heavy storm like we had yesterday.

I should add that my entire development/neighborhood was built near a sand mine and everyone has similar problems with the foundations; however, many do not know because previous owners walled over the cinder block walls with sheet rock etc….now they also have a mold problem.

I considered two solutions:
1) Hire a contractor to excavate around the entire house, weather proof the cinderblock from the outside and re-grade the lawns. I don’t have the cash for that. I saw that on Holmes Inspection on HGTV!
2) Extend the existing downspouts into the center of the yard by connecting them to some large diameter PVC and burying it under the lawn. In other word re-create what they originally did in ‘54. That seems fraught with peril if the pipe gets obstructed or crushed etc.

Bring on the suggestions, please.

[guido]

Our house is about the same vintage and has the same style cinderblock foundation. One of the previous owners put in french drains on the uphill outside and all of the downspouts are lead probably 30 feet away from the foundation. Other than one freak year with a 3" inch rainstorm on well frozen ground and runoff from the property next store, we have not had any water in the basement in 18 years. We also have diverters that let us collect rain water to barrels that let us do most of the watering on the property.

[thollandpe]

Your option 2 is precisely what the previous owner (and builder) of my house did for our neighbor’s house. He was a brilliant engineer and did the site, drainage, and buried utility work for the whole neighborhood. So yeah, that’s what I’d recommend.

Don’t oversize, stick with 4” pipe, because with gentle pitch you still need some velocity in the pipes to keep them clean. I’m amazed whenever I inspect our cisterns and pipes how clean they are. We have a leopard frog resident in one, maybe that’s my caretaker. I prefer ABS because PVC is poison to the people who make it.

Except that cistern is in my yard, on the uphill side of my foundation.

My long story is that the outlet from that cistern was severed by the morons the previous owner hired to remove the buried oil tank so he could sell us the house 15 years ago (in November). That January the basement starts leaking and I discover the cistern is overflowing and saturating the ground uphill of the foundation. So with temps in the teens I have to half submerge myself into that water to get an inflatable plug into the inlet.

Come spring I hand excavate the outlet pipe, discover the missing section that takes about 15 minutes to fix (4” ABS and two Fernco couplings). And then discover that the system actually serves the neighbor’s house and crosses property lines, that there was a “gentlemen’s agreement” about installation and maintenance costs, and that the present neighbor knows nothing of it either and is not a gentleman.

If I ever meet the morons who excavated that tank, and decided to bury a broken pipe rather than tell a 93-year-old man they broke it, I will give them a good what-for.

[rwsaunders]

You can make sure that the interior drain is properly working to start, as excavating the entire foundation and properly waterproofing the CMU will be costly, but it is the ultimate long-term solution if you’re staying put. No coating placed on the inside of a basement wall can prevent water from entering. Rain leader drain pipe of that vintage was clay or cast iron, with cast iron being too costly for storm drainage, so you’re at the end of the pipe’s life cycle. Replace the clay pipe with solid PVC and lead to a discharge source…the PVC pipe won’t get crushed or obstructed if properly bedded. Does your rain leader pipe lead to a storm water connection at the street? You might have to contact your municipality if you’re making modifications. My Borough requires all home sales to scope (camera) the rain leader pipe and replace damaged sections as a condition of closing.

[Too Tall]

This past (Pandemic) year I hand dug and installed nearly 150' of French drain. Option #2 is your best bet. If you have a strong back do it yourself. Either water the area you will dig or wait for rain to ease the digging.

The basics are very well documented on youtube or just ask Todd or myself.

I choose to build for the next family, the system is way overbuilt. One French drain is infact connected to one downspout becuase that had nowhere else to go. Because I overbuilt the system and graded the yard to pitch twords the drain it serves to keep the foundation nice and dry.

It is a very satisfying thing to walk around the property and watch the water NOT accumulate ;)

Best thing ever? Now that the garage is bone dry I can get someone in to grind the concrete floor to prep. for some fancy surface treatment. I'm thinking fluro green specs. with a dark blue background.

[j44ke]

I've now seen some very nice installations of PVC half-round gutters and downspouts around here. They seem to have a dramatic advantage over all those aluminum gutters in that they are fit together and sealed (and don't get bashed bent dented loosened etc.) and then they run directly into storm drains out into the yard with dry wells or perforated pipe at their terminus.

How long does a cinder block foundation last? At 67 years and with a history of leakage that predates your ownership, I'd wonder how the mortar and exterior block faces are doing.

[jclay]

2) Extend the existing downspouts into the center of the yard by connecting them to some large diameter PVC and burying it under the lawn. In other word re-create what they originally did in ‘54. That seems fraught with peril if the pipe gets obstructed or crushed etc.

That. I suggest:

• Schedule 40 PVC for mechanical strength/crush resistance, not thinner wall stuff (you don't need Sch 80). HDPE of similar wall is very tough and suitable but not as easy to deal with for the DIYer. I've never used ABS. Glued or fused joints only, below grade and go to the trouble to properly bed and cover the pipe so it doesn't fail. Use sweep ells (preferred) or at least long radius ells.
• Install cleanouts and connections as necessary to allow snaking the entire length from down spout connection to whatever the other end is; tees, wyes, whatever it takes and make the buried pipe connection to the downspout above ground and as easy to disassemble/reassemble/see leaks as possible. Sometimes cleanouts oriented in opposite directions are necessary. It's very cheap maintenance insurance.
• Without knowing the peak flowrate we can't (I certainly can't) really know what ID to use. The 4" recommendation by thollandpe (size and reason) feels kinda in the ballpark but double check locally. I never did gravity flow pipe design off of roofs for this kind of service, professionally (process industry pressure piping only), so I don't have a feel for it.....and a roof can capture a heck of a lot of water in a downpour so larger wouldn't surprise me. It can all be calculated so check with the folks who do it and look at installations in your area. There are some on-line gravity flow calculators you can use to get/check the design details (ID, slope & and any bends) for reasonableness. What size was the original clay pipe? Does the entire roof drain to a single pipe for delivery to the cistern? Getting this line sized properly for partial fill flow is important. Is/was the clay pipe vented (if only casually by a loose fitting connection to the down spout)? Making partially filled gravity flow pipes work properly in other contexts requires venting of some sort; I don't see why this would be different. It might be that the down-spouts provide adequate venting but I don't know. Again, check around.
• Research the recommended invert (slope) for this type of service; I assume (as a discussion starting point only) it would be similar to household waste plumbing...which I forget but is easily found. Make the pipe invert uniform, no humps or dips.
• Utilize, or don't fight, the existing grade to whatever degree possible...so, reroute to best advantage if/where you can?
• Leaf screens for the gutters so you're not fighting leaves inside the pipes?
• Do you want to retain the cistern? I mean, is it worth the trouble? Or just get the water far away? Does "center of the yard" get the water to an opposite slope?

If you post pics/diagrams you might get some addnl ideas.

Good luck with it.

[thollandpe]

PS You can also consider air knife or hydrovac excavation, also called slot trenching, to expose your foundation. This leaves a much narrower trench, and you can leave your plantings in place. I've seen this done to reinforce and waterproof rubble foundations with two-part urethane foam. The foam is cheaper than the recipe used inside the house because it doesn't need additives for fire resistance and such.

[Bobonli]

Thanks. I have some weekend reading and researching to do. Good to know I was on the right track.

The cistern tank is gone, collapsed way before I moved in, leaving something of a sink hole in a corner of the yard. The original system was downspout > clay pipe > cistern ( the water dept told me the practice at the time was to bury a 50 gal drum) > then more clay pipe underground to the curb on the street where there’s a drain hole. In my entire neighborhood there’s maybe 3 houses where that curbside drain actually drains water. Most of these systems collapsed over time and just sank into the yards. Every now and then while gardening we’ll dig up a hunk of clay.

[Bobonli]

PS You can also consider air knife or hydrovac excavation, also called slot trenching, to expose your foundation. This leaves a much narrower trench, and you can leave your plantings in place. I've seen this done to reinforce and waterproof rubble foundations with two-part urethane foam. The foam is cheaper than the recipe used inside the house because it doesn't need additives for fire resistance and such.

I’m guessing this ain’t cheap. Having just replaced the roof, I’m not sitting on a lot of extra cash but just looking at the labor involved it has to be costly not to mention disruptive to excavate the perimeter of the building. ALthough the water intrusion is most noticeable on the backside of the house, there’s evidence of the same on two other walls in the basement.

[Bobonli]

Update and another question:

The storms last week exacerbated matters. I had to emergency dig two 15 foot trenches to extend the downspouts away from the house. That worked for about 2 hours before they were overwhelmed and water was back at the foundation and oozing into the inside wall. I called the company that installed the water guard (what I called the French drain) for the previous homeowner, hoping they might have a drainage and intrusion solution. The product they recommend is a vapor barrier installed over the interior wall, tucked into the water guard channel. They don't do exterior waterproofing or drainage work.

This seems wholly cosmetic, but maybe I'm not thinking clearly. So water will still leech through the cinder block foundation, but i won't see it on its way to the water guard and sump pump b/c it will be on the other side of the vapor barrier.

Any thoughts?

Now I have to track down either an irrigation contractor or landscaper to figure out how to mange the water and the slope of the lawn because obviously 15 feet is not enough extension from the building.

[SlowPokePete]

Check out a company called Connecticut Basement Systems...they worked on our house in Yorktown and totally solved the water problem in our basement with their system.

Prices were competitive and reasonable, too.

They have many patented products and the guy came and flat out said "You will never see water on your basement floor again. Ever."

and he was right...

https://www.connecticutbasementsystems.com

SPP

[Bobonli]

Check out a company called Connecticut Basement Systems...they worked on our house in Yorktown and totally solved the water problem in our basement with their system.

Prices were competitive and reasonable, too.

They have many patented products and the guy came and flat out said "You will never see water on your basement floor again. Ever."

and he was right...

https://www.connecticutbasementsystems.com

SPP

ROFL. That looks bloody familiar. Here's who just left my house: https://www.healthybasementsystems.com

[SlowPokePete]

That's pretty funny indeed.

I know the guy who started CT Basement patented a bunch of products and maybe still owns it?
\
Anyway, good luck water problems are a challenge for sure.

SPP

[Too Tall]

I've now seen some very nice installations of PVC half-round gutters and downspouts around here. They seem to have a dramatic advantage over all those aluminum gutters in that they are fit together and sealed (and don't get bashed bent dented loosened etc.) and then they run directly into storm drains out into the yard with dry wells or perforated pipe at their terminus.

How long does a cinder block foundation last? At 67 years and with a history of leakage that predates your ownership, I'd wonder how the mortar and exterior block faces are doing.

Do tell. This fall I'm either going to have downspouts made or make them myself. We have quite a few runs to deal with. PVC intrigues me.

[j44ke]

Do tell. This fall I'm either going to have downspouts made or make them myself. We have quite a few runs to deal with. PVC intrigues me.

The ones I saw up close were being used by a contractor working on our house for another project. I have never thought the flat bottomed metal gutters (just seem to collect crap, even with gutter covers) made much sense to me, nor did the flimsy connection of most metal downspouts (friction fit, crimp, screw, clamp, caulk - still seems to fall apart.) The gutters this guy had joined together like PVC pipe except that they also had some interlocking shapes that fit together and along with glue created a smooth seamless joint that allowed water flow uninterrupted. They looked pretty trick actually. And the material seemed like it had a different level of durability. That's my impression at least, and the contractor said he liked installing it.

The stuff I saw on a house (sort of a contemporary farm house) that impressed me ran all the downspouts directly into the ground, and from there, I assume, daylighted somewhere well away from the house - or into a storm drain or dry well or cistern. No downspouts flowing out into the yard or even open at the bottom over a storm drain grate. A closed system from the gutter to the ground. Made sense to me - I assume there must have been a clean-out somewhere - as you simply have much better control where the water goes. Into a gray water cistern, for example, for watering the lawn when needed. Just looked like a really clean and sensible way to do it.

I am sure there are limitations or problems that appear in the long run. I don't know how many colors it comes in, for example. Or if you can paint it. They aren't hand-soldered copper gutters, but in white, they weren't offensive.

[thollandpe]

...they weren't offensive.

I'm offended by PVC because of its toxicity to the people who make it. Seriously, it's a ticking time bomb and we're kicking the can down the road (holy mixed metaphor, Batman!) by continuing to use it.

On a gutter system, I'd be really concerned about PVC's tendency to expand and contract with temperature swings and sag over time. If you've ever used plastic decking or PVC trim you'll know what I'm talking about.

I'm pretty sure you can get a half-round shape in seamless aluminum.

[j44ke]

I'm offended by PVC because of its toxicity to the people who make it. Seriously, it's a ticking time bomb and we're kicking the can down the road (holy mixed metaphor, Batman!) by continuing to use it.

On a gutter system, I'd be really concerned about PVC's tendency to expand and contract with temperature swings and sag over time. If you've ever used plastic decking or PVC trim you'll know what I'm talking about.

I'm pretty sure you can get a half-round shape in seamless aluminum.

I guess I'm using PVC as a generic term. I don't know that they were PVC. I just assumed. Plastic. Looked like the Bianchi green water pipes that were used on our house for draining stormwater away from the house underground, only they were white, smooth finished and didn't have the typical writing on the pipe.

But if they were PVC, then I guess that's one of the limitations - toxicity and temperature.

[ides1056]

I used galvanized steel, bought at a local farm supply in Amherst. Also copper, a long time ago when it was affordable. These will last a lifetime. The steel eventually corrodes, and I paint it with an acrylic roofing membrane I buy from Resource Conservation Technology. I also use this paint on standing seam galvanized roofing. The pipe in the ground is flexible and comes in very long rolls. Black plastic. Put in cleanouts in obvious places. Not sure what type but not PVC.

[thollandpe]

I used galvanized steel, bought at a local farm supply in Amherst. Also copper, a long time ago when it was affordable. These will last a lifetime. The steel eventually corrodes, and I paint it with an acrylic roofing membrane I buy from Resource Conservation Technology. I also use this paint on standing seam galvanized roofing. The pipe in the ground is flexible and comes in very long rolls. Black plastic. Put in cleanouts in obvious places. Not sure what type but not PVC.

The black flexible plastic is probably ABS, which is not on the Red List published by the Living Futures Institute. Solid sub for PVC.

Half-round galvanized gutters are gonna be bomber, but you can't sweat them together like copper. But aluminum is an infinitely recyclable (and mostly recycled) material.

For those of you worried about physical trauma to aluminum gutters, is that from ice dams? If so, the gutter is not your problem.