Structural questions about excavation and gunite

schwimmen

Bronze Supporter
Jan 30, 2017
104
Houston TX
#1
We are attempting to finalize our permit with the city but need some feedback on building close to house/fence and piers.

The excavation will be be within five feet of house and side fence. With our small lots, that’s a given, and it’s done regularly here in Houston. The city will likely require a structural engineer to sign off, but I’m not clear what they’re even looking for from the engineer - steps that will be taken to shore up the soil during excavation, additional rebar/gunite in the walls, or some combination thereof??? The guy at the city didn’t seem to know.

He he also mentioned seeing piers on plans in the city. We have a soil report and have moderately (not highly) expansive soil. While it would be great to have them, I’m not sure if they’re necessary/worth the expense.

Much thanks for any feedback. If anyone has had a good experience with structural engineers in Houston, recs would be appreciated.
 

kimkats

Mod Squad
LifeTime Supporter
Jul 10, 2012
35,556
Tallahassee, FL
#2
If there are any windows or glass doors right by the pool they may need special treatment-glazed glass or such.

If there is any way to find and talk to an inspector they should be able to tell you what they will be looking for.

I hate being so vague :( but really don't know the answer. Just hoping this will help lead you to someone that might be helpful.

Kim:kim:
 

riley00dog

Gold Supporter
Nov 14, 2017
2,207
Brisbane, Qld, Australia
#3
We dug about 1.8 metres from the side of our house. All pools here need to be signed off by a structural engineer and approved by council. We had about 5 pb out to quote. We received different information from different pbs. We knew we wanted a bench the length of the pool, so we ended up putting that along the house side so we were only digging down about .65m on that side. I’m not sure of the ramifications if we chose no bench or the other side. Possibly piers would have been necessary, but our ‘soil’ is shale so it’s pretty solid. Funnily enough most of the other pbs mentioned our boulder retaining wall as a potential issue on the other side. When our plans were submitted it wasn’t an issue at all. Maybe we did end up being far enough away. I would run you ideas through a structural engineer and see what they say. It may mean you have to modify your pool layout to work with the proximity to the house (e.g, shallow end closest) or maybe piers or maybe nothing will be needed. With slightly expansive soil though you want to do things by the book.
 
#4
Here is a diagram of my town's regulations on this. Basically, the intention is that if the pool is too close to the house, the pool has to be engineered to be able to bear the weight of the structure. You can have a shallow pool close to the house, or a deep pool far away from the house, but if you want a deep pool close to the house, you are going to have to build it beefy.

Angle of Repose - Pool Close to Structure.jpg
 

Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
4,375
Central California
#5
The city will likely require a structural engineer to sign off, but I’m not clear what they’re even looking for from the engineer - steps that will be taken to shore up the soil during excavation, additional rebar/gunite in the walls, or some combination thereof??? The guy at the city didn’t seem to know.
Well, if they're anything like the planning dept's I've worked with, all they're looking for is the engineer's stamp on the plans, literally. It's no surprise the guy didn't know, they generally don't. And don't care. This is about liability. With the engineer's stamp on the plans, the liability for anything that goes wrong will be on the engineer, not the city. So in essence, it's an insurance policy for the city that they make you pay for! And the engineer will have you overbuild things so they stay in the clear. Not an indictment of the system, just the way it works. You end up with a nice sound structure, but it'll cost ya. The source for the answers to your questions is probably only going to be the engineer himself... Planning department employees have basic knowledge of construction and codes, beyond that, they rely on architects and/or contractors to know what they're doing, or foist the real work onto engineers, at your expense.

I got half way through a deck repair and then got red-tagged. The county required a permit, and an engineer. (The two decks were on the second and third stories of my house.) All I was doing was replacing rotted wood, not changing the design. Didn't matter. I grumbled and groaned. And it was $2K in permits and engineering by the time I was done (as much as the materials!). But after I was finished I had to admit the decks were stronger and safer than I would have left them... What'da ya gonna go?

The engineer I used studied what I had done on site, and came up with plans that accommodated my work. So I didn't have to redo anything. Which was cool. I got the impression that he would have done it another way if I hadn't already started, but he made what I had done work. Which then gave me the impression that there's some wiggle room in how they do what they do. Point being, if the engineering requirement from one guy challenges your budget, I think you could ask him for an alternate, less expensive solution. Or go to another engineer for a different angle. I don't see why you couldn't get a preliminary take on the approach to the project, along with some rough construction costs, from more than one firm, before you commit to the full engineering suite, and associated cost. Similar to how you would get bids from multiple PBs before you outlay any cash to build. I don't know if engineers offer free estimates quite like that, but they can't expect customers to commit without some advance idea of projected costs. Otherwise, you could be at the mercy of whatever firm you choose, have to pay them the full price for the plans, and be stuck with plans that crush your budget. So in other words, continue to seek for a good reference, but don't just settle for that alone, shop the job around and base your choice on the estimate for the plan, and an estimate for projected construction costs for that plan (which might have to be worked out with the PB).

I've never actually done what I'm suggesting, I'm just brain storming an approach that might work, or at least something to ask about, before you plunk down more money than you might actually need to...
 

setsailsoon

LifeTime Supporter
Oct 25, 2015
574
Stuart/FL
#6
Schwim,

I'm sure you'll hear a lot of horror stories here about incompetent building departments and such with this question. My advice is to get a structural engineer to look at the design to do a couple of things:

  • Recommend installation requirements that will ensure no damage can occur to the house foundation
  • Determine minimum requirements for any structural components so the pool integrity is ensured
  • Provide an unbiased design. The engineer will consider cost and design integrity.

This is a very beneficial thing for you to have when you are dealing with contractors that are driven at least in part to maximize profit. Experienced and successful builders usually are conscientious and know reputation is huge but there are exceptions. You don't know them 'till it's really too late to change. So having the 3rd party qualified engineer working only for you is a very good thing to do. Make sure the engineer can show successful experience in pool design for your area.

I hope this helps.

Chris
 

Dirk

Gold Supporter
TFP Guide
Nov 12, 2017
4,375
Central California
#7
Chris, do you think it's possible to "shop" engineers in advance of paying them, to at least get a general idea of costs (both for plans and construction)? I think it's safe to assume that there is more than one way to engineer just about anything, which means total cost could vary accordingly, even dramatically. How does one determine ahead of time the best engineer to use, in terms of costs, qualifications and approach to--solution for--the task?