Removing old carpet adhesive from a concrete floor.
Digressing from journalism for a while. I am trying to remove underfelt adhesive from a concrete floor. The previous carpet layer glued foam sheet to the floor. I've managed to remove the foam, scraping it off with a sharp shovel, but how on earth do I remove the adhesive. Apparently, it must be removed prior to laying new carpet.
Tried scraping and sanding. Short of a heat gun producing toxic fumes any ideas on the best way to remove this stuff.
I assume it is a contact adhesive type? Similar to Selleys Kwik Grip? The advise about removing the adhesive first, what was the reason or basis for removing it? I personally wouldn't be concerned too much about removing the adhesive if you are laying a new foam underlay directly on top of it. I cannot anticipate any issues in doing that. The same goes for laying carpet directly onto the concrete (with adhesive still on it). As long as the surface was flat.
Edit: are you planning to glue the new carpet to the slab? If so I still cannot foresee any issues with leaving the old adhesive in place.
Last year I removed an old vinyl layering on concrete and it was glued. Removing the glue was quite difficult as I needed to remove for preparing to tile.
I found mineral turps to work. Basically pour onto the floor and wait a few minutes and follow up with a heavy duty broom (thick bristle) with the rubber strip on the back. This worked well.
At a previous house I lived in, the guys short cutted by not removing the old glue and glued over the top. The glue reacted and about a year later, carpet was beginning to "pocket" (honeycomb underneath) and became a trip hazard. I suspect the reason you would remove the old glue is perhaps incompatibility with a previous product reacting with a new glue. Anyway, just my experience which resulted in a $1000+ re-layering exercise.
Thanks guys. We have been told by the company laying the carpet to clean the floor back to bare concrete, perhaps for the reasons Darren quoted. Still, I agree, underlay over the top with no adhesive shouldn't pose a problem. I'm trying cloudy ammonia right now followed by a scraper. But turps sounds like a good solution too. Just as well I have a big fan to ventilate the room.
A citrus based solvent might work ( based on d-limonene). It's not so harsh and more pleasant to use.
I remember scraping down an entire house after the previous owner glued a rubber backed carpet straight onto the wooden floorboards. Took weeks to clean.