Pool Demolition - need help bidding

[1toomanyhobbies]

I have a guy that wants me to bid on demo'ing a pool. It isn't a large pool but it has a jacuzzi built in and the thing is build solid. It looks like the sides are a foot thick and most likely reinforced with rebar. The jacuzzi will about have to be destroyed by the time I take 2 to 3 feet off the side. I'd be doing it with a bobcat 335 and renting a breaker. The guy is planning to eventually put a cement driveway over this area. I know you need to put holes in the bottom and take at least 2 feet off the top. When you put the holes in the bottom, you have the cut away the rebar as well, right? When you take off the sides, you use the hammer, scrape away concrete, use the saw to cut the rebar, then scrape away the rest of the concrete?

I included the skidsteer in the picture for perspective. The bush hog on the skid steer is 5 feet wide. The pool is about 10 feet wide, 9 feet in the deep end and maybe 25 feet long. The jacuzzi on the side is about 4.5 feet inside diameter and concrete on the sides connecting to the pool. I am trying to figure out what to bid on the project. I figure one load of gravel for the bottom, and 4 loads of fill dirt. I'd be renting a breaker, skidsteer compactor, and concrete saw to cut the rebar. If renting the equipment would cost $500ish and the rock and dirt $1000, any input on what is should bid for the rest?

 

[SeaMac]

I'm not sure how they build pools in NC but down here in Florida the walls aren't as solid as one would think. They're usually only wire mesh around the perimeter and the aggregate is sprayed on then floated smooth. Once cured it is hard as a rock. There is limited rebar usually only #5, spaced round the perimeter but I don't remember spacing at it's only used tie the deck and coping down. They're actually very easy to demo at least down here. I generally have only done the electrical bonding but have been onsite through every phase of construction and again I have no idea if they build 'em the same way up there. Sorry if this is of no help...

 

[1toomanyhobbies]

Let me rephrase the question. How many hours do you think it would take to put the holes in the bottom and take 2.5 feet off the top of the pool including the jacuzzi? This will be my first concrete demo so my guess could be wildly off. 12 hours with hammer on excavator, 12 hours cutting rebar/scraping concrete/loading up concrete. 6-8 hours putting in grave/dirt and compacting in 10 to 12 inch lifts. Am i in the ballpark? The guy wants a final, no matter what happens price so I was thinking $5500 to give me some room in case I encounter something unexpected. Does that sound too high from a value perspective?

 

[Dozerboy]

I would just leave the concrete fall into the bottom of the pool and put grave over that then dirt. Your timeline overall sounds ok, but I have never done a pool with that small of iron. And it really depends on how good you are with a breaker. I'm pretty good on one and am easily twice as fast as our greener hands.

 

[1toomanyhobbies]

I would just leave the concrete fall into the bottom of the pool and put grave over that then dirt. Your timeline overall sounds ok, but I have never done a pool with that small of iron. And it really depends on how good you are with a breaker. I'm pretty good on one and am easily twice as fast as our greener hands.

The only thing I'm concerned about leaving concrete in the pool is that the customer plans to eventually put a concrete driveway over top. I'd hate to have the concrete in the pool settle some over the years and warp/crack his driveway. Am I being too paranoid or is that a valid concern?

I have not used a breaker before. If a job should take 12 hours and it takes me 16, I don't mind eating the extra hours because I'm new to the attachment, I just hate to bid 12 if it should normally take 20.

Anyone else have thoughts based on the pictures or past experience?

 

[1toomanyhobbies]

I'm not sure how they build pools in NC but down here in Florida the walls aren't as solid as one would think. They're usually only wire mesh around the perimeter and the aggregate is sprayed on then floated smooth. Once cured it is hard as a rock. There is limited rebar usually only #5, spaced round the perimeter but I don't remember spacing at it's only used tie the deck and coping down. They're actually very easy to demo at least down here. I generally have only done the electrical bonding but have been onsite through every phase of construction and again I have no idea if they build 'em the same way up there. Sorry if this is of no help...

Thanks for the input. I haven't been able to break the pool wall to verify but I've seen enough pools built with rebar that I'd hate to bid thinking it will be mesh and then end up finding rebar.

 

[Hendrik]

I did a pool a while back https://www.heavyequipmentforums.co...-Magic-trick-making-a-swimming-pool-disappear took less than a day from go to whoa.
However the pool had concrete around the top and the walls where metal and no jacuzzi, however my KX41-3v weighs 1600kg, your Bobcat weighs over 4000kg so should be able to do more. Plus I did not have to bring in any material to fill the hole.
I would not think that the rebar will be that strong, as it is not a weight bearing structure. I would be thinking about building a earth ramp to drive the ex into the pool and pull the sides down from the inside, either that or dig a trench around the pool and pull the concrete back.
Also be careful when cutting rebar, sometimes it is under tension and can pinch the blade or spring back, generally cut it 3/4 of the way through and then use the ex to break it fully.

 

[1toomanyhobbies]

Also be careful when cutting rebar, sometimes it is under tension and can pinch the blade or spring back, generally cut it 3/4 of the way through and then use the ex to break it fully.

That is great info, thank you for sharing! The concrete is 12 inches thick so I'm not sure if the mini can pull it down with rebar in there or not. I had planned to do exactly what you mentioned about making dumping in some dirt to make a ramp to get inside so I could put the holes in the deep end. I hadn't thought about pulling on the sides to see if they would break away. I have my mini onsite for another project and have scraped at the concrete some but didn't take much time. I think the next time I am there I will spend some time to see if I can get a small part down to the rebar.

 

[Hendrik]

That is great info, thank you for sharing! The concrete is 12 inches thick so I'm not sure if the mini can pull it down with rebar in there or not. I had planned to do exactly what you mentioned about making dumping in some dirt to make a ramp to get inside so I could put the holes in the deep end. I hadn't thought about pulling on the sides to see if they would break away. I have my mini onsite for another project and have scraped at the concrete some but didn't take much time. I think the next time I am there I will spend some time to see if I can get a small part down to the rebar.

The concrete may appear to be 12" thick on the top but you may well find that lower down the concrete is thinner.
What you can try and do, is to dig the soil away from the end near where the skiddy is parked and try to pull the top towards you because of the curve at that end you need to pull away from the pool, whereas in the middle where it curves back into the pool you need to pull towards the pool, if that makes sense. Unfortunately in this situation you can't use your bucket curl to lever, this is the most powerful thing an ex can do, remember to dig you backfill blade in to stop the ex sliding as you try and pull the top of the concrete.
Far as compaction goes, non dramas, once you got some busted concrete in the deep end, chuck some soil on it and then use the ex to compact it, thing is to place the concrete so it can't collapse as you compact it, basically like any other compaction job, do a layer at a time.

 

[CM1995]

All good advice. The pool is probably gunite and will break easily. The rebar is probably #3 and won't give you much problem. Of course as soon as I say this it will have #5's on 1' centers, at least that is the way it goes for me..

The jacuzzi will probably give you the most trouble as it looks like it will need to be totally demo'd.

Personally, I would drop the load of gravel and just backfill with dirt unless the owner requested stone. I did a rough calculation and it comes to 95 CY +/- with a 15% swell. Depending on your final grade, you may want to add another load of dirt for backfill if you hauling it in your tandem. I didn't take into account the concrete in the volume calculation but I like to err on the higher side when giving a firm bid.

Knock you pool walls down at least 2' below final grade so you can create a cohesive fill layer over the old pool. Cut a bucket width outside the pool walls and key your fill lifts in as you come up with backfill. Use the existing soil you cut in your backfill, blending it with your import material. This will help bridge the old pool area into the existing soil. A Bobcat 48" vibratory roller attachment will work well for compaction, I have one.

Lay your concrete pieces as flat as you can, starting in the deepest portion of the pool. Once you get your concrete demo'd and placed, put a 1' bridge lift of dirt over it and compact the hell out of it. The vibratory roller will work the soil around the pieces. Make the remaining lifts 8" loose.

Your bid sounds right at $5500, of course depending on how far you have to truck your dirt and what kind of access you have to the pool. Check your rental rates, $500 sounds low to me for what you will be renting.

I second the idea of using torches to cut any rebar instead of a saw for the reasons Hendrik posted. A saw around here rents for about $70 per day, I don't know what a set of torches rents for or even if you can rent them, since I have a set already. If you don't have a set of torches you may want to buy a set, work some of the cost into this job and have them for the future because if you run iron, you them.

 

[robin yates uk]

how deep is the remaining water? I ask this because breakers dont like to be immersed. a couple of inches to 6ins is ok but anymore and the hammer won't like it

 

[1toomanyhobbies]

CM - lots to good info. i do have a cutting torch but the tanks are too big to get into the pool. I could look into the price of getting the baby tanks. That is an interesting idea.

If I fill over the concrete, as long as i compact the dirt above you don't have any concern of it settling over time? The gravel is something I read about on a website dedicated to pool demo. i don't care either way, I just want to do a good job.

I had mentioned the $5500 price to the guy and he about croaked which is why i am trying to see if I am grossly misjudging the project. He mentioned having a bulldozer demo it when he has the plot landscaped...I have never seen a bulldozer demo a pool I don't think it would work we with reinforced concrete. I full size excavator might be able to demo it without a breaker but still, would their overall cost be that much cheaper? The guy knows very little about pool demo so i don't think he had any concept of what the cost would be. I had originally planned to bid $3900 until I realized I'd basically have to completely demo the whole jacuzzi. I'd like to do the project as a good learning experience and one more thing to add to my advertised services. Think I'd be losing my shirt at $3900?

 

[CM1995]

Just some rough numbers in my scatterbrained head :tong

6 tandem loads of fill @ say $200 per load - $1200 (of course this depends on a lot of variables)
Mini ex and skid @ 2 days, 8 hrs per day $65/hr each (on the low end) - $2080
Rental equipment - $500
Manual labor 8 hrs @ $25 per hour - $200
Torches and or saw - $100

Grand total before O&P - $4080. 25% O&P of $4080 is $1020 for a bid total of $5100. That is without any CYA's or any unforeseen issues. You can eat $400 real quick doing something like this which is why I thought your $5500 bid is a good number.

Now my scenario is what it should be, in a perfect economy and we all know that we don't have one. Your $3900 amount would be close if you were working for T&M and not assuming any risk of a hard bid. Times are tough and this is one of those tough decisions.

A hard bid is a hard bid, you underbid it and you eat the costs.

 

[1toomanyhobbies]

Just some rough numbers in my scatterbrained head :tong

6 tandem loads of fill @ say $200 per load - $1200 (of course this depends on a lot of variables)
Mini ex and skid @ 2 days, 8 hrs per day $65/hr each (on the low end) - $2080
Rental equipment - $500
Manual labor 8 hrs @ $25 per hour - $200
Torches and or saw - $100

Grand total before O&P - $4080. 25% O&P of $4080 is $1020 for a bid total of $5100. That is without any CYA's or any unforeseen issues. You can eat $400 real quick doing something like this which is why I thought your $5500 bid is a good number.

Now my scenario is what it should be, in a perfect economy and we all know that we don't have one. Your $3900 amount would be close if you were working for T&M and not assuming any risk of a hard bid. Times are tough and this is one of those tough decisions.

A hard bid is a hard bid, you underbid it and you eat the costs.

Thank you CM, this was very helpful to see how you figured the numbers. It is a hard bid which is what concerns me the most. I don't mind just covering T&M, because of economy etc I am ok with that. My fear is the unforeseen issues like you said and being stuck suddenly dumping in 10 - 15 extra hours.

 

[Dozerboy]

I don't know about demoing the pool without a breaker. All the pools I have done where with 20ton+ hoes and I wouldn't of wanted to do it with anything smaller. I broke a few keeper off the teeth too. Using a breaker you defiantly don't need to haul off the concrete the pieces will be very small if done right.

 

[Hendrik]

There is a surprising number of vids showing pool demo work http://www.youtube.com/watch?v=zAVF5N5SZek&feature=related not sure if that will help you or not?
Ahh yeah you need a wrecking ball http://www.youtube.com/watch?v=TOiu4LGqT8w&feature=related

 

[InsleyGuy]

Stand your ground on price! I was asked to demo a 30+ year old gunite pool as part of a larger job, figured I would cut down along the outside with my d4h dozer then just push the sides in. I couldn't even hardly chip the top edge. A90lb jackhammer just bounced around. Ended up using a Tak tb-68 mini with a breaker and a 580d with thumb to rake/ pull out the debris. Punched holes every 1 foot horiz. and vertical. Rebar was 12" o.c. both ways. Concrete was the hardest I've seen in 40 years of construction, and didn't want to seperate off the rebar. Personaly I think your mini might a bit small for this. Demo is hard to bid because you really don't know what your going to find, and the job can head south real fast! Don't be afraid to just walk away, or do it h/rt only. I hope I never have to do another one. Tom

 

[eric12]

what if you just break up the floor of the pool, the top 2 feet and the hot tub. put it all in the pool and fill with flowable fill. then if the customer wants to put a driveway in he can doze out what he needs put stone in and hes ready to go. thatll save a lot of labor time compacting and messing around with dirt for under a driveway

 

[InsleyGuy]

I think Eric actually has a pretty good idea. Punch a bunch of holes in the bottom, don't worry about the rebar or removing sections. Break / pull the sides and jaccuzi all in to a consistent depth below finish grade ( I still believe that will be harder than it looks). Put the flowable fill in to form a "plug" that won't settle over time, then use your choice of material to bring everything up to grade. And again, don't short yourself on the price. Maybe T&M would be the fairest way to both you and the customer. Tom

 

[1toomanyhobbies]

Two questions. First, the guy is trying to do this as cheaply as possible and wants to not take the sides down two feet. I have told him that is the recommended way to do it and is code in most major cities. He just wants holes in the bottom and the decorative brick on the top taken off which would leave it 2 inches below grade. I have told him i can't be responsible for any problems that may occur and that the utility companies would have to run lines around the pool but he wants to do it this way. Can anyone see any major catastrophies from doing it this way?

Second question is since I am not going to have a lot of concrete, would sand work well instead of gravel? There are a lot of piles of sand on the property from when I golf course was build years ago. Sand usually drains well so i am thinking if I can combine it with the concrete then I should be ok. Thoughts?