demolition and re-use

getfit

I am in the process of bidding on a site - I am very determined, but have my upper limit and will stay sensible. One of the "factors" I am trying to cost is slightly unusual for an a-typical site in Ireland.

There are a a few block built sheds in the site from a time it was used to house animals (years and years ago). The sheds could come to over 2,000sqft if I were to make a guess. Single story, flat roofs, empty.

Now my questions are
1. What would be the cheapest and most sensible way to pull them down?
I know I could attack them for the price of a sledge hammer and wheel barrow and chip away myself (knock with sledge and drag away rubble in wheel barrow) - but that could be over a week of back breaking work. Could I get a guy in a JCB to floor them all in an afternoon? Could I rent some machine from hire outfit and do it myself???

2. What happens to the blocks???? The guy who is selling the site suggested that you could use a good portion of it as infil in the floor of the house and garage... I've been thinking about this - is it a good idea or are the blocks a really bad form of infill - should i just stick with the normal type of hardcore stone??? Also, I was thinking I'd "seperate" any blocks that were still in tact and possible use them as building blocks for boundary walls etc. around the house.... is that just silly on my part?

3. The house will be built on parts of where the sheds used to be. Would this involve digging up all of the old foundations of the sheds (assuming they have foundations) or just digging up where the foundations for my house cross the old ones. I'm assuming this isn't the biggest deal in the world as the guy clearing the site/digging the foundation trenches will just need to work and extra day to clear a bit deeper. Am I over simplifying that job???? The last thing I want to start doing is under estimating the cost or the work involved in any spect of the build...

Thanks for any advice anyone can give on any of the questions

Cheiftan

1. Get a 20 tonne track machine , tractor and dump trailer and pull them down , should'nt take longer than a day.

2. I personally would'nt use broken blocks in a sub floor , I know people who have but from a purely engineering viewpoint most blocks are only 5 N or less if they are older and its far from ideal to have that in your sub floor, a better way to use them would be to put a haul road around the outside of your proposed buildings footprint, cheaper than hardcoring and will do in that situation quite well. As for re using blocks well, thats up to you . How much time do you have ? how much pain can you take !! ? Its not something I would consider doing, you'll end up stacking them on a pallet and moving them a dozen times before you may use them if at all then you'll wonder why you went to the bother in the first place.

3. I'd take out all the old foundations as it could lead to problems later with differential settlement.
These existing foundations have been there for years and have more than likely settled as much as they are going to , you will be pouring new founds which then start to settle beside or on top of the old ones , cracks will surely follow. For costing allow say two days at most for ripping out old founds, again using 20 tonne track machine and 4wd tractor and dumptrailer.

best of luck

getfit

Thanks a million for that advice.

You have re-inforced my fear of using the blocks in the sub-floor - thanks.

That was a great suggestion about using the blocks for around the footprint of the house. Also, based on the fact some people have risked using blocks as subfloor for their houses I would probably use the blocks as sub-floor for the garage...

Considering brand new blocks cost about 60c each, it does seem too much work spending hours reclaiming something bought so cheaply, you're right about not wasiting my energy - you're still going to have to pay a lad over €1 to lay them!!

I wouldn't mind doing a lot of the grunt work on taking the buildings down and moving the rubble, but whoever I get to do the job up to subfloor - I'll probably get them to dig out the old foundations also....

reilig

getfit wrote: »

I am in the process of bidding on a site - I am very determined, but have my upper limit and will stay sensible. One of the "factors" I am trying to cost is slightly unusual for an a-typical site in Ireland.

There are a a few block built sheds in the site from a time it was used to house animals (years and years ago). The sheds could come to over 2,000sqft if I were to make a guess. Single story, flat roofs, empty.

Now my questions are
1. What would be the cheapest and most sensible way to pull them down?
I know I could attack them for the price of a sledge hammer and wheel barrow and chip away myself (knock with sledge and drag away rubble in wheel barrow) - but that could be over a week of back breaking work. Could I get a guy in a JCB to floor them all in an afternoon? Could I rent some machine from hire outfit and do it myself???

2. What happens to the blocks???? The guy who is selling the site suggested that you could use a good portion of it as infil in the floor of the house and garage... I've been thinking about this - is it a good idea or are the blocks a really bad form of infill - should i just stick with the normal type of hardcore stone??? Also, I was thinking I'd "seperate" any blocks that were still in tact and possible use them as building blocks for boundary walls etc. around the house.... is that just silly on my part?

3. The house will be built on parts of where the sheds used to be. Would this involve digging up all of the old foundations of the sheds (assuming they have foundations) or just digging up where the foundations for my house cross the old ones. I'm assuming this isn't the biggest deal in the world as the guy clearing the site/digging the foundation trenches will just need to work and extra day to clear a bit deeper. Am I over simplifying that job???? The last thing I want to start doing is under estimating the cost or the work involved in any spect of the build...

Thanks for any advice anyone can give on any of the questions

Hi getfit,

Just some advice for you that might help you to save some money.
If I were you, I would just hire in a 10 tonne digger - it would be half the price of a 20 tonne and will probably do the dame amount of work, especially in demolition were there wouldn't be much heavy digging going on. It will also be sufficient for digging the foundations, smaller, easier to manouver around the site, and more accurate for digging. Main thing is to keep away from a jcb, there really are only good for digging holes that you are too lazy to dig with a shovel and not practical for demolition or foundations.

I really don't think you will need a dump trailer. Get the digger driver to use the demolished blocks around your house (not in the floor) - if he puts down large gauge hardcore or blast rock (which is cheaper) to make your driveway or to clean up the area around the house, you can put the old blocks on top and just get the digger driver to pack them in with the bucket and track over them - they will break down very small and make great blinding.

Dig all new foundations, use the old ones that you take up to fill into the foundations - if they are mass concrete, they will be perfect for filling up to the floor level and will save you a fortune on hardcore filling for this.
What would you need the dupm trailer for, you have nothing to move, just recycle what you have and save money on hardcore and on waste disposal costs. Does it say in your planning that all materials from the site should be used in the new development?

Final advice, when hireing a digger, make sure the driver has a lot of experience. A guy with 10 years experience on a 10 tonne can do a lot more work than a guy with 1 years experience on a 20 tonne.

Daniel

muffler

As said get a digger and you can either stockpile the rubble for your own use at a later date (maybe for raising external ground levels) or get someone who wants the rubble for filling to take it away. As they are getting it free they can supply tractor/trailer or lorry.

Do not under any circumstances use the rubble for sub floor filling - huge risk of wood disease attached to it.

Dig out the founds (if any) of the old buildings and start completely in the new.

getfit

Whats wood disease???

muffler

getfit wrote: »

Whats wood disease???

The most common one you would be familiar with is "dry rot". If this is present in the timbers of an old building then there is a damn good chance of it manifesting itself in the new build if the demolished rubble is used as filling internally.

May not be as risky nowadays with the use of radon membranes but I haven't seen too many membranes/DPM's fitted properly.

You have been warned!