Looking for advice on finish elevation

[slipnfall]

Hi folks - I hired an excavator to remove all organics and get me down to a solid, (close to) level base for my pole building. It's excavated 1ft over all around.
I'm a little hung up on surrounding grade and where to set finish floor height. Front right corner is the highest surrounding grade, with front left of building ~7" lower. There's an 8' porch on the left that's shallowly excavated, but surrounding grade there is nearly 11" lower than highest (font-right).

My plan was finish floor (concrete) 6" above highest surrounding grade. But that would put front left corner (inside concrete) nearly 11" high (7"+6"). Outside the porch, I can only adjust grade so much near that left-hand tree. Even factoring the porch being 3-4" lower than inside finish floor, that porch would be pretty high.

So, considering that front right corner seems to be a bit of an outlier, I'm thinking just setting inside finish floor 2-3" above that highest. At least I won't have to grade up surrounding everywhere else so aggressively? And the rest of the building would still be*well*above surrounding to avoid water ingress.

Does this seem like a valid, calculated risk?

PS not that it matters for the above questions but FYI I'll be bringing sub-base up with recycled concrete, with 4-5" 3/4- beneith 2" XPS, then 4-5" concrete. Also due to site restrictions this was the only place to build. Lack of trees otherwise this the decision to try to keep them.

Thanks in advance.

 

[NUTTSGT]

Starting from scratch, I would want 12" finished floor height compared to surrounding grade.

Porch height, I would make 1" lower than finished floor height. ... I'm guessing this is a lean to porch on a post frame ? You do not want porch floor and finished floor height the same... especially you don't want them poured level and at the same time. You will fight water intrusion under the wall.

Looking at the pictures on my phone so it's hard to see your issue.

 

[slipnfall]

Starting from scratch, I would want 12" finished floor height compared to surrounding grade.

Porch height, I would make 1" lower than finished floor height. ... I'm guessing this is a lean to porch on a post frame ? You do not want porch floor and finished floor height the same... especially you don't want them poured level and at the same time. You will fight water intrusion under the wall.

Looking at the pictures on my phone so it's hard to see your issue.

Thanks for the reply. Correct, concrete slab under lean-to, to be poured separately/outside building.

So let's assume porch concrete is set 1" lower than inside finish height, and I set inside finish height 6" above highest surrounding grade. That would put the front left corner of the porch 11" above surrounding grade. I guess the problem is grading 9ish inches down by the tree. Actually maybe that's not as bad as I thought now that I think about it...

 

[NUTTSGT]

Keep in mind, some trees don't like a lot of soil over their roots. So do a little research on the tree type and take that into consideration. I'm not sure exactly what your plan is, skill level or financial status but you could create a landscape feature around the tree to keep excess dirt off the roots.


The other thing to bring up the grade around the porch or atleast that end is to add river rock 1-2" in size along the porch edge. It looks nice and helps with rainfall drainage. I don't have gutters on the sides/back of my shop and have 12" of river rock from the wall/foundation. I dug down 12" to basically form a 12"x12" trench and put a 4" perforated tile at the bottom, filling with river rock. Rain comes off roof, onto, through river rock down to the tile and away down the tile.

 

[billconner]

I'd go 2 to 3" higher. I don't think 6" is enough, but I've always lived in snow country.

 

[slipnfall]

Keep in mind, some trees don't like a lot of soil over their roots. So do a little research on the tree type and take that into consideration. I'm not sure exactly what your plan is, skill level or financial status but you could create a landscape feature around the tree to keep excess dirt off the roots.

Exactly. I should have been more clear but this is my main issue with the porch being that high: I don't have the room to the left to gradually (plans call for 5% for 10' out) grade out 9-12" without potentially smothering surface/feeder roots.

 

[slipnfall]

I'd go 2 to 3" higher. I don't think 6" is enough, but I've always lived in snow country.

That's a good point I hadn't considered until now. For better or worse this region of MD doesn't get regular significant accumulation (or drifting to significant depths).

 

[jack stand]

It's a common, easy and expensive mistake to build too low.
I'd add at least 6" to your best guestimate. Several loads of dirt and gravel is a whole lot easier than the alternative of being too low and having a wet floor, area around the building and puddles that are always there.
I'm not saying that there aren't conditions where this will affect drainage around other buildings or conditions, but as a stand alone project, higher is always better.
Trying to move surface water 15' away with only 2" of fall is not the situation you want to have.

 

[coldh2o]

I'll echo all the other comments, you do not want to go into this compromising drainage for one tree. You could build a well around the tree so you're not covering the roots, but I would just remove it. How close is it to the building?

We built our house, and then the shop a few years later, with the intent to minimize tree cutting. What a mistake. Every spring for the last 10 years, we're pruning trees or taking them down completely as they grow and get too close to the house, or die and become a hazard.

I'd have the floor at least 12" above surrounding grade.

 

[billconner]

If there are reasons to not get it too high - like driveway - then do masonry walls. Mine is cut into grade and I have a minimum of two courses of block all around and 7 courses at rear corner - gives me a minimum of a foot above finished grade all around. It is stick framed, not post frame. Not sure of details for a post frame building. Maybe raising it is only solution.

 

[wssix99]

For a pole building, I would excavate a little more around the high sides and build a retaining wall around those high sides. I'd then set the building level with the low ground so there is a small dry moat between the retained high ground and the building.

For the elevations here, a simple block retaining structure should be fine and would give a lot of flexibility.

 

[iagsxr]

Within reason you'll never be sad that your floor's too high.

The original part of my shop was built too low or I should say the street in front of it was raised after it was built. Makes everything drainage related a challenge.

 

[LiketoFix]

A lot of Good suggestions here.
Was an Excavating Contractor for several years with a lot of Concrete work Experience. Not sure where your at but total Moisture Rainfall/Snow per year and what your total weather is year round means a lot. Looks like a great site, location, that you picked out.
We had a rule of thumb that we always worked to. "Better Higher than Lower." With that being said it looks to me that your excavator did a nice job for you and placing his spoils out of your way for the Construction is a must. Remember if you go a little higher, (12" for example), you can always re grade on final grade around the perimeter to finish off the project. I love to save trees as much as I can but that one tree wouldn't determine my Elevations! The landscape Idea around the tree is noteworthy also to try to save it. You have good options. Proper Drainage is everything, no matter how much rainfall you get, it's just more important if you get a lot of Rain! IMO!
Good Luck!
LtF

 

[billconner]

For a pole building, I would excavate a little more around the high sides and build a retaining wall around those high sides. I'd then set the building level with the low ground so there is a small dry moat between the retained high ground and the building.

For the elevations here, a simple block retaining structure should be fine and would give a lot of flexibility.

This is what I was going to do if I'd done post frame. Since grade was near 3' above floor, was going 4' to wall, with gravel, geo textile, and drain to daylight.

 

[LiketoFix]

As a Successful Contractor and always helping Customers out trying to answer their questions Professionally and looking at their projects how I would do it if it we're mine was always a major concern. Estimating and understanding what the customer wanted and needed was a very big part of my experience in my position when I was asked "What and How I would do something."
Steps and Retaining Walls can be a nice effect and very useful when needed but also can add a degree of possible extra cost, maintenance, and extra work that's sometimes unnecessary or not needed. However in landscaping to round out a grade nothing looks better than a well maintained terraced stepped down retained area.($$) These topics came up regularly with Customers and understanding their Budget and needs was a large part of my Job.
Pole Buildings are a great Idea eliminating a lot of $$$ for foundation Work and done properly will last a long time. In many cases when I'd shoot the grade for people with a Laser Level I could show them what elevations I would suggest and What I would do if it was mine and how to give them what they we're looking for within their Budget,($), and Time frame. IMO!

Hi folks - I hired an excavator to remove all organics and get me down to a solid, (close to) level base for my pole building. It's excavated 1ft over all around.
I'm a little hung up on surrounding grade and where to set finish floor height. Front right corner is the highest surrounding grade, with front left of building ~7" lower. There's an 8' porch on the left that's shallowly excavated, but surrounding grade there is nearly 11" lower than highest (font-right).

My plan was finish floor (concrete) 6" above highest surrounding grade. But that would put front left corner (inside concrete) nearly 11" high (7"+6"). Outside the porch, I can only adjust grade so much near that left-hand tree. Even factoring the porch being 3-4" lower than inside finish floor, that porch would be pretty high.

So, considering that front right corner seems to be a bit of an outlier, I'm thinking just setting inside finish floor 2-3" above that highest. At least I won't have to grade up surrounding everywhere else so aggressively? And the rest of the building would still be*well*above surrounding to avoid water ingress.

Does this seem like a valid, calculated risk?

PS not that it matters for the above questions but FYI I'll be bringing sub-base up with recycled concrete, with 4-5" 3/4- beneith 2" XPS, then 4-5" concrete. Also due to site restrictions this was the only place to build. Lack of trees otherwise this the decision to try to keep them.

Thanks in advance.

Slip,
You've got a beautiful setting and a well thought out planned Site. I also think your smart for asking suggestions and opinions.
It's all about what you want and how much you want to spend. Keep it Simple, affordable and less Maintenance down the Road so you can spend your time enjoying what ever it is that you like. IMHO!!!

LtF

LtF