Asphalt cracking following laying of laminate flooring

[Zingari]

OK chaps I have to admit that DIY is not my strong point. Despite my father-in-law being an instant expert who tends to disagree with me and any subject matter experts it's often easier to get someone in.

Now last year (less than 12 months) I had some very nice laminate flooring (it's like Amtico) laid in the hall and kitchen.

The house is 1970s with solid floors and the black DPM top coat stuff. So to prep the floor it was screeded before the adhesive was applied and the flooring laid in strips.

It is great stuff, very solid with no echo etc. Anyway last week in the light I noticed that two areas had become raised (like big air bubbles - distinctive hollow sound) in the hallway near to the edges by the skirting boards. The firm has been back today, removed the laminate, chipped away at the screeding that has lifted off the floor. Underneath has revealed some cracks in the asphalt/DPM.

The company say it is the asphalt/DPM at fault and the cracking has caused the screed to lift and separate. Solution would be to remove all the laminate/screeding get someone in to sort the asphalt and then re-lay the flooring.

I'm not convinced the floor has suddenly just done this without some sort of reaction to the screeding etc? There are no pipes, wires etc under the floor and the floor has not been subject of excess water other than light mopping.

Can anyone please offer some advice

 

[WoodYouLike]

Right, the old bitumen - lets just screed over it - issue.

What screed did this company use and did they use a primer before screeding?

 

[Zingari]

Not sure on the screeding/primer but will find out. I know that when it was put down I couldn't walk on it until it had gone off.

Also from taking some up today and removing some screeding to expose the bitumen underneath if I tap the bitumen it sound hollow. Hence the company is saying that it cant be the screeding as this has bonded to the bitumen top surface.

I've now gone around tapping all over the hall and there are definite patches that sound hollow, most towards the edges. This is not sounding good even though the screed is a good half to a quarter inch thick

 

[lymmranger]

Could you please give out some more info...

1/ was the subfloor "ashphalt" or "bitumen"

2/ was the new floor "stuck" to the screed? or was the screed just used to level the floor?

3/ what tests did the installer do before starting?

....the only comment I would offer is that you have done the correct thing - you entrusted a company to supply and fit a product. Unfortunately for them something has gone wrong. Even more unfortunately for them it is not your problem its theirs!!!!

....Assuming the above is correct and they did the "whole" job then they should rectify at their cost and this is what you should be pushing for

 

[Zingari]

Could you please give out some more info...

1/ was the subfloor "ashphalt" or "bitumen"

2/ was the new floor "stuck" to the screed? or was the screed just used to level the floor?

3/ what tests did the installer do before starting?

....the only comment I would offer is that you have done the correct thing - you entrusted a company to supply and fit a product. Unfortunately for them something has gone wrong. Even more unfortunately for them it is not your problem its theirs!!!!

....Assuming the above is correct and they did the "whole" job then they should rectify at their cost and this is what you should be pushing for

The floor is a typical 1970s composite construction - which I think is concrete with a black bitumen top coat that acts as a DPM? It was in fairly good order as before this work it has always been covered with carpet and the only impregnations was from the carpet grippers.

I was informed that the screed was used to level off the floor and provide a smooth 'key' so that the new flooring could be bonded (glued) to it in strips.

I am not aware of any tests the installer did before starting the work. If the solid floor was faulty I would have expected the matter to be raised at that point saying it needed to be prepared/repaired.

It now sounds to me that having taken some floor and screed up where the hollow sound is they are saying that the bitumen has 'lifted' from the concrete sub base hence the sound and it is not their fault.

What I cant understand is if the screed was put down to level up the floor (and it was perefectly flat when laid) how and why the bitumen (if it is this) has suddenly decided to lift?

This floor was not cheap - I paid circa £2k for the hall and kitchen.

 

[WoodYouLike]

If my guess is right, it is down to the screed used that is now affecting the bitumen. We've seen it happening before (and before and before)
Troublesome stuff really, bitumen.

 

[lymmranger]

Ok you have confirmed that "the whole job" was carried out by your supplier.....

I am afraid (for them) that it up to them to rectify the situation.
They are (supposedly) the experts.
They will(or should) have come round to look athe job before they quoted.
They quoted you a price to do the job to completion which you accepted.

So....

....Complain and insist on them putting the job right. Do it quickly and if you feel they are fobbing you off put it in writing

 

[glueman]

Because asphalt is an unbonded sub floor, ie it is not stuck to the concrete slab, just floating on a fibre carrier. Any cracks that are in the asphalt from perhaps, gripper being nailed down, will be stressed when a smoothing underlayment is applied. With all smoothing underlayments there is a small element of shrinkage when they dry. This will pull at any slight cracks and lift the asphalt of the carrier. As the previous contributors stated, it is the responsibility of the installer to check for cracks prior to screeding. If the asphalt had been intact then it wouldn't have been a problem. I assume it is flooring grade asphalt and not the roofing type that some of the less reputable builders use.

 

[Zingari]

Thanks guys for the replies so far. I have now had a damp proofing company in for their assessment.

Their view is that the membrane laid between the concrete and the soil/hardcore foundation may have decayed allowing dampness to permeate through the concrete to the membame under the asphalt. This could have created air pockets cauing the asphalt to lift away from the concrete and hence effecting the screed/new flooring.

They stated this could have been going on for some time and with carpet it has not been noticed. I'm not convinced on this point as I would have either noticed it when the carpet was removed prior to the screeding and given that a self levelling compound was applied would this not have levelled out any unevenness?

Also if there was a damp issue why is it smack bang in the middle of the hall but next to an internal wall where carpet gripper would have been? Equally there is no damp at all in any of the walls etc.

I'm still of the opinion that this has arisen from the preparation and laying of this flooring but resolution to confirm the damp company's opinion would involve excavation of the floor in the affected area and great expense.

Can anyone offer advice on some options/resolutions.

 

[glueman]

I'm not so sure that these people are telling you the truth! Asphalt was primarily used because it was cheap, clean and seam free. It was also an ideal damp proof membrane over floors that did not have one laid originally. Therefore to say that it is damp that is causing the problem is not true. Asphalt can cope with damp, the problem as I see it is due to cracks in the asphalt. The drying and shrinkage of smoothing underlayment will lift the asphalt off the concrete base because it's integrity has been weakened by the cracks.

 

[crumble]

Hi - WoodYouLike - I saw you mention in a previous post that the screed used could be affecting the bitumen... I'm having a problem with my flooring and wondering if you might have any ideas (//www.diynot.com/forums/viewtopic.php?t=276917)

Thanks

 

[tim00]

This post intrigues me so with respect to all the other posters and their expertise:
1. 1970's solid floors were built with membranes in-situ, asphalt is a remedial measure.
2. when was the asphalt laid and why?
3. Is this an extension?
4. if no membrane present then moisture could be penetrating the slab and the area where the asphalt is cracked - in that case, preparation prior to laying the asphalt would seem to be the key to what is happening.
5. trapped moisture will bubble any floor covering or screed.