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Joined: Jul 2002
Posts: 8,443
Likes: 3
Trumpy Offline OP
When my wife and I eventually build a new place, I was toying with the idea of a basement office.
Now basements are very few and far between down here in New Zealand, I'm not sure why.

How much, is involved in the up-keep of a basement?
Are they hard to keep dry?, hence the sump pump.
I realise that new things have been invented for water-proofing in the last 5-10 years.

What I don't want to have happen is ending up with a damp, cold area that could be rendered un-inhabitable.
Does anyone here have a reasonably new basement that is warm and dry and how did you achieve this?

Sorry, this is a huge question, but I'm genuinely inquisitive as to how a good water-tight basement is acheived, I want to run computer gear and some AV gear down there if possible.


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Joined: Jan 2005
Posts: 5,445
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Cat Servant
Assuming your ground is suitable for a basement, there is no reason a basement cannot be as pleasant as the rest of the house. The key is your ground water levels.

Simply put, no amount of waterproofing will keep a basement dry, or structurally sound, if the water table is above the level of the basement. Even temporary increases in the water table - such as might be caused by a heavy storm, or seasonal runoff - vastly increases the challenges.

Assuming you have a good site, comfort is the result of three factors: lighting, ventilation, and insulation.

"Insulation" is the tricky part. You're best served by spacing your wall coverings off the foundation walls, leaving an air space between for moisture to drain. Likewise, the floor is best built up over the cement slab, leaving a small gap around the perimeter.

Joined: Apr 2002
Posts: 7,386
Likes: 7
I used a basement office for years, with no issues.

Take heed in what Reno says above....ground water could be your worst enemy.

A lot depends on your local building codes.....

I have seen quite a few 'finished' basements done up really nice. Home theaters, tile floors, nice bars, etc. The other end of the spectrum is quite a few (older homes) that had very serious flooding/water problems, causing extensive damage.

New homes; some are 'grade access' from the side or rear, some are 'one flight down'; a few come thru with seperate entrances, and roughing-in for sure looks like a 2nd kitchen....hence an illegal apt or 'two family'.

Good luck if & when you do it

Joined: Feb 2003
Posts: 939
I have basement and have no issue however the critail situation is the water table level and proper drainage that two key items you have to watch out otherwise Reno hit on the target with the details.


Pas de problme,il marche n'est-ce pas?"(No problem, it works doesn't it?)

Joined: Jul 2002
Posts: 8,443
Likes: 3
Trumpy Offline OP
Hey thanks a lot guys for your input.
The water table thing may explain why basements are not that common over here.
New Zealand (being an island nation) has an un-usually high water table, near the coast, that does vary considerably, especially during the winter months.
This is why I was asking for some advice from those that have been there before.
I'd sooner not take an expensive gamble and have it turn to custard, after all one end of the house would be built over this basement.
I've had a word to a local structural engineer today and she didn't like the idea, in theory, let alone practice.

I guess it's back to the drawing board then.

Joined: Jun 2006
Posts: 613
No engineer without experience thinks anything is a good idea. Here we use a perimeter drain buried around the foundation walls just below the footing levels. Add drain rock and filter cloth and you can keep a basement very dry. The concrete is waterproofed (read resistant) on the outside with a waterproofing chemical that looks like very runny roofing tar. It is applied with a roller.
There are some different interior things that can be done to make an air break between the concrete wall and the interior finish. There are insulated Styrofoam forms that both insulate the basement and provide concrete forms. Of course what ever method you use to ensure it is dry has to be accepted in your building codes.
So what do you do with the water collected by the perimeter drains? In a perfect world they would gravity feed to the storm sewer but the sewer might be just for waste water. the sewer might be higher than the perimeter drain and require a pump that can keep up with the flow. You also have to control the runoff from the roof so it also flows away from the foundations. If you are prone to power outages then you will also want back up power for a pump since storms power outages and excess water often come as a party.
There are a lot of ways to deal with ground water and maybe the hardest part if finding someone competent where you live to design a system to protect from water inside the basement. Find someone with experience in your part of the world and you can have a very warm and dry basement. Or maybe cool and dry would be better?
Basements are very common where ever we get frost. The advantage is the house is supported on the ground below the frost line so the frost won't move the house or crack foundations.
I live on the southwest corner of Canada where frost is very rare, near sea level, and most houses here are slab on grade or have only a shallow basement a few feet into the ground.

Joined: Jul 2004
Posts: 9,942
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If you can drill a well with a post hole digger you can't have a basement. They end up being indoor swimming pools.

Greg Fretwell
Joined: Mar 2005
Posts: 1,213

I think frost lines are another large part of it. For many areas in the northern US, you need to sink footings several feet underground to get beneath the frost line, with reinforced CMU walls from there, with several feet of space to allow a crawlspace for maintenance and installation. Once you've done that, you might as well just make it a basement!

Areas that are flat, hot and/or have high water tables do not often have basements.

All the above unfortunately apply to me. I miss having a basement frown

Joined: Feb 2008
Posts: 165
The basement is my man cave

Joined: Jan 2005
Posts: 5,445
Likes: 3
Cat Servant
I've been following the show "Holmes on Homes" lately, and he has some interesting points about building in a basement.

Or, for that matter, building atop concrete at all!

First off, not all basements are the dark, dank, deep pits you might imagine. Indeed, it seems that, in most cases, the slope of the land results in one wall usually being pretty close to 'grade' level.

The basement remodel begins with installing a 'French drain' around the perimeter of the house, slightly below the level of the basement floor. This drain is intended to keep water from accumulating around the basement at all.

The basement wall is sealed on the outside with something that resembles tar or pitch, then a 'waffle' pattern plastic sheet is set against the wall. This, I believe, is to prevent the dirt itself from damaging the tar coating.

Inside the basement, Mike Holmes parts with 'conventional wisdom' and speaks against placing any manner of plastic sheet on the floor or walls as a 'vapor barrier.' His opinion is that these simply trap moisture, and lead to a mildew issue.

Rather, he sets rigid foam insulation directly on the concrete, and tapes the seams. This provides a 'vapor barrier' on the 'warm' side of the foam. He does encourage the use of radiant heat in the floor, in part as this will dry out any moisture that may get there.

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