The Old Floor Heave

[RL Costa]

5,300 sqft. Freezer Older design (30 years) polystyrene sandwich between a double concrete floor, about a 4" plus heave at the middle of a 25' section running 50'. we have excavated the first layer. what's next?

RL

[monkey spanners]

I have heard of people connecting ark welders to the re bar in the concrete to get some heat into it and melt the ice.

[Magoo]

Hi RL Costa
Once you have dried everything out, seal lower concrete with a resin concrete sealer, check and fill cracks. Replace lower vapour barrier ( polythene sheet ) tape them and seal. Install new high density polystyrene, top vapour barrier sealed again to top existing, Pour new wear top slab with slow cure concrete reo etc.,. Allow several weeks to cure and start the slow pull down procedure run room at above zero and watch new slab doesnt shrink. Then seal joints with a flexible sealastic filler.

[RL Costa]

No rbar in the first layer? only a light gage mesh (pig fence). Actually thinking of leaveing the heave alone and getting the vapor seal and putting a spray self leveling foam insulation in and pouring the new concrete slab?

[RL Costa]

Hi RL Costa
Once you have dried everything out, seal lower concrete with a resin concrete sealer, check and fill cracks. Replace lower vapour barrier ( polythene sheet ) tape them and seal. Install new high density polystyrene, top vapour barrier sealed again to top existing, Pour new wear top slab with slow cure concrete reo etc.,. Allow several weeks to cure and start the slow pull down procedure run room at above zero and watch new slab doesnt shrink. Then seal joints with a flexible sealastic filler.

Thanks for the advise. very much appreciated. I recieved the qoute to do the a spray in place-way to much $$. I will get some pricing on the high dense polystyrene.

[monkey spanners]

Are you going to have a heater in the new floor to prevent it heaving again?

[CHIEF DELPAC]

I had a blast freezer with floor problems. The concrete was removed. the frozen sand was removed. I was going to hook up to the existing under floor heating system but it was not feasable. Electric heating was looked into, but it was found to be cheaper to dig up the floor and renew it as needed rather than installing a electric under floor heating system. So thats what was done. The floor consist of a vapour barrier, insulation and a concrete that is mixed for cold service. No problems so far. CD.

[Magoo]

Hi Cheif Delpac.
The problem if you big into the lower construction floor and expose base course, is 1/ structural strength and. 2/ vapour barrier. Get one or both wrong , you have a major long term problem. Some thing like vent tubes, electric trace ( multi-circuit for redundancy ) or piped heated glycol circuits. Should already be installed. So if you expose lower base course you have now screwed the whole anti-freeze system.
Getting the construction / lower concrete slab sealed is a big problem. Apart from the fact that concrete is poruos for a start, so seal new conrete after cure period with a resin sealer.
Add to all the above is the winter ground frost permifrost level. Worked in Siberia and ground permifrost was 2 plus metres, ( in winter it was colder outside than in the coldstore.).

magoo

[CHIEF DELPAC]

Magoo The freezer I was describing is a combination of a batch blast freezer and part of a IQF freezer. There are five blast freezers in a row that the IQF belt runs through. The freezer was added to icrease tonnage of the IQF system. The freezer was installed next to the original four freezers. It was built in a former production area, there is no underfloor heating or ventilation. The original concrete was not meant for cold temperature service. The original floor was 30 plus years old. The floor was failing, it had several large cracks and had lifted in several spots. Part of the floor had been taken up to reach the 25K volt power line that supplied the plant power.That being done it was decided to remove the floor for the repair in my last post. The new concrete was sealed. CD.

[riazahmadmalik]

Though we are putting up a new project - we have used ventilation pipes (slotted) using natural draft air. This is below the insulated flooring.
The hot / ambient air will be in contact with the concrete below the floor and the gravel will not ice because of the heat exchanged.
For any assistance please email at intrstat@lhr.comsats.net.pk

[georgedvf]

Hello guys! I see this is old post, but I have one question about the floor insulation system.

I see you talk about underfloor heating or ventilation, I've heard that when using Extruded Polystyrene there's no need to have any of those heating or ventilation systems because the water absorption of the polystyrene is very low. Do you recommend to do this (not installing heating system underfloor) when using polystyrene to insulate the floor???

[lawrence1]

Some freezer stores i have been involved in have slotted pvc pipes one metre apart in gravel beneath the lower base slab and one end of these rise 6 metres to the top of the building and are painted black to absorb heat during the day to create air flow,the other ends are cut at ground level and are fitted with fly mesh,,,,works well to warm the ground to prevent ice heave and no power costs.
Lawrie