/diy/ - Do It Yourself

[Anonymous No.1532764]

How do I build an underground house which doesn't flood or get damp/mould?

(I hear you can avoid planning permission if you build down rather than up)

[Anonymous No.1532766]

Like a house with a basement.

[Anonymous No.1532775]

>>1532764
Realistically, you don't. You could go cheap and try the Oehler PSP method, but water infiltration will always occur with underground structures.

[Anonymous No.1532793]

>(I hear you can avoid planning permission if you build down rather than up)
Whoever told you that meant "don't get caught." You won't do this in a city lot without your neighbours making a fuss. And if you're so far off grid that you don't have neighbours, then nobody will be around to care.

>How do I build an underground house which doesn't flood or get damp/mould?
Concrete will crack eventually, and it's porous. The waterproofing layer that is normally painted on the exterior of concrete basements isn't a permanent solution, like my leaky basement showed last year.
Dry underground construction requires good drainage, normally this is done with gravel and drainage tile. I've heard of more exotic systems use an air gap, which lets moisture fall straight down to the tile drainage instead of being forced through foundation cracks by hydrostatic pressure. Similar to a double wall.
The "roof" of your underground structure needs to shed water and not allow it to pool. Maybe cover it with 1/4" polyethylene sheet, or metal plate, or a bentonite geotextile.
If you're on a hill you can drain downhill. If you're on flat land without good soil drainage, who knows, pump the water far away from your dwelling.
You could build rooms out of underground water or fuel tanks, I guess. You can get those in large diameters, double wall, 10+ feet or bigger, big enough to give you floor space and head room.

Avoiding permits is not your biggest concern when doing a project this big.

[Anonymous No.1532822]

I'm trying to figure this out right now.

I bought a house that has a detached garage, with a concrete walkway between the back door & man door on the garage.

Turns out there's actually a tunnel leading from the house basement to a basement room under the garage. The tunnel has block walls (one of which is pushing in), dirt floor, and the 'roof' is the concrete walkway.

The walkway is old, cracked & corroded, so rainwater just drips through.

Now that I know it's there, the first thing seems like I'll have to waterproof the slab/ceiling, and fix the drainage on both sides to halt the wall collapse.

Not sure what after that... cement floor in the tunnel maybe, and fix the sagging wall somehow.

Fun project for the next few months, anyway.

[Anonymous No.1533067]

>>1532764
>(I hear you can avoid planning permission if you build down rather than up)
Also known as how to spend an extra hundred thousand dollars to avoid paying a $250 filing fee and having a half-blind inspector come out and rubber stamp all the shit you were going to do anyway.

[Anonymous No.1533121]

>>1533067
But depending on where you live, not having any visible dwelling (or decent looking dwelling if they find one) on your property seriously drives down property tax.

[Anonymous No.1533129]

>>1532764
For drainage you can build a, uh, I forget what it’s called, but old houses used to dig a super deep hole nearby and fill it with gravel to help drainage. Drain any odd water pooling areas into this hole and BLAMMO. You’re G2G.

This project is totally absurd though, between the added cost and things that could go wrong, I’d opt for a small house with a big basement.

[Anonymous No.1533252]

>>1532764
Location-choose a hill, set bunker
Spray with roof cement, cover with 10mil plastic, protect with foam. Cover it
Always choose the high ground

[Anonymous No.1533862]

>>1532764
>I hear you can avoid planning permission if you build down rather than up
Enjoy having your tons of dirt collapse on you in your sleep.

[Anonymous No.1533872]

>>1532822
Depending on the level of work you want to put into it, you could consider totally redoing the tunnel into something more like a subway tunnel, i.e. a circular tunnel in the style of bored tunnels. The roundness means the force is distributed across the surface differently and would be less likely to cave in over time.
Alternatively, you could actually raise the roof/walkway so that it sits slightly above the rest of the land, so rain would be far less likely to slip in.

Another potential option is to expand out the walkway/roof so it hangs well past.

But these are all fairly intense remodeling, so it might not be what you are looking for.

[Anonymous No.1533878]

>>1533067
Isnt it sad taht in the land of the free weve gotta worry about inspectors and codes and all that shit

[Anonymous No.1533885]

>>1533878
Pisses me the fuck off anon, can you imagine if our forfathers could see us now. Fucking shame

[Anonymous No.1533888]

>>1533878
I agree to some extent, but some regulations I don't mind.
Specific example, I own two properties surrounded by acreages, and existing regulations prevent the neighbours in both areas from subdividing and densifying just to make shekels.
I'm in Canada and for all the shit we get about being an overregulated refugee dumping ground, I've seen lots of cheap offgrid land without zoning, oversight, or scrutiny. 95% of the country is sparsely populated.
Some places are so buttfuck rural that you don't need require a permit to build, some aren't even zoned. There are people all over the place living in the woods in offgrid cabins.

[Anonymous No.1534678]

>>1533878
Personally, I WANT strict building codes in my community.
>be me
>live in upscale, conservative, right-wing, southern town
>conservative politics highly concerned about maintaining high property values
>building codes require best building practices, called "code plus".
>inspectors crawl up your ass at the smallest detail
>home plans and style must pass review board to make sure it maintains the continuity of the community, AKA acceptable standards.
>cheap shit materials prohibited
>sloppy, git it dun quik work not allowed
>only top shelf work allowed
>strict zoning restricts commercial development to 2 small locations. Shopping malls/strip malls not allowed (we don't want cheap, shabby retail shitting up the view)
I'm quite happy not having low rent apartments, poor niggers and white trash, pig farms, trailer parks, and general suburban sprawl shitting up my community.
Being a wealthy elitist is a good thing.

[Anonymous No.1534689]

>>1532764
one word: shipping container

[Anonymous No.1534695]

>>1532764
Exterior river stones || truckbed liner spray || reinforced cement || spray foam insulation || truckbed liner spray || interior
Encircle with drainage pipes.

[Anonymous No.1535226]

>>1532764
>doesn't flood
good drainage. build on/in hillside or high ground, so rain water will naturally run off. also dig down several feet deeper than your planned slab/foundation. Throw in a drain pipe or two, and backfill it with rocks and gravel.
>or get damp/mould
good ventilation. A bunch of vent pipes to the surface, and/or a big, open facade with lots of doors and windows like your pic. You should probably plan to install a dehumidifier too.

[Kevin Van Dam !ZNBx60Gj/k No.1535244]

>>1533872
Give it a couple years and Elon Musk’s Boring Company will come get that shit done in 15min and give you a quick connect to LAX for another $30k.

[Kevin Van Dam !ZNBx60Gj/k No.1535247]

>>1534678
Ummm so does the charter explicitly say “No Negroes” or is it just implied?

[Anonymous No.1535297]

Geotechnical engineer here.

There would most likely be more red tape for this type of building approval, not less. Large excavations require much more experience and knowledge to manage compared to traditional above ground construction, mostly to do with lateral ground support (shoring), groundwater management (pumping) if you are near the groundwater table, and surface water management.

Regarding materials you will be relying heavily on large amounts of concrete with mega attention paid to construction joints and the waterproofing. The current best practice for waterproofing and gas-proofing concrete (yes, concrete is permeable) is to impregnate a geofabric material with a spray-applied polyuria membrane in a sufficiently thick layer (several mm) at least. This then has to be smoke-tested from beneath to ensure to gaps.

In short the design, construction and quality-control processes for building below ground are many many more times more complicated and costly than traditional construction, and the only reasons you would want to do it is for extreme edge-cases of property location and/or if you're a multimillionaire embarking on some wild dream.

Not to mention the lack of sunlight without design a series of reflective-lined vertical tubes leading to the surface, which also end up acting as seepage pathways and erosion channels.....

[Anonymous No.1535381]

>>1534678
Gentrification is the best thing ever.

[Anonymous No.1535383]

>>1535297
>building approval
>in BFE

top kek

[Anonymous No.1535392]

Make the walls and roof and floor out of thick steel.

[Kevin Van Dam !ZNBx60Gj/k No.1535397]

>>1535381
Yeah, when white people with money move into a neighborhood and drive all the trashy people out, not when the city rats move into a quiet suburban neighborhood.

The only problem is you displace all the nogs when you do that. And the only place to put them is semi-rural areas where property is still cheap and it’s profitable for the slumlords. And of course they bring the hood with them, so it ends up turning these real quite barely-suburban areas into shitholes.

[Anonymous No.1535832]

>>1533129
Dry well

[Anonymous No.1535836]

I live in a berm home anon. The back and sides are in the earth but I have have a "traditional" truss roof. The only way to keep your in ground house dry is drainage. This includes good drainage at the foundation, drainage to keep water from flowing to your house and a deep roof line or gutters to carry that water away. The key is to keep water away from the structure.