Reason for crumbling concrete porch floor

[gkingg]

First time poster and home owner, please be gentle!

My house was built in the 1980s. I am trying to find out why the concrete floor in my porch is crumbled and/or cracked around the edge.

The porch is separated off from the main house with an internal door and isn't heated. The floor has been painted with floor paint (which is the black and grey bits).

I recently pulled the old carpet up and found the edge of the concrete floor next to the door and the external wall cracked and/or crumbling. When I pulled the cracked bits up there was some rubble and possibly soil around the edge.

I think cold/water is being let in from the external brick/mortar at floor level because it looks like there are some holes/chips in it. I have tried to get a bricklayer to come over and have a look, but no one wants to

I would be super grateful if you could take a look at rhe pictures and let me know if I am on the right track! If so, I plan to fix the external brick/mortar and then fill the internal gaps with cement.

Attached pictures show:
1. Internal porch and cracked floor
2. Some of the goodies that were under the cracked pieces of floor
3. The external side of the porch
4. Some of the damaged external brick/mortar that I think is causing the problem

Thank you!

 

[desertrose]

Hi @gkingg - wondered if you got anywhere with this? I have a similar sort of porch and problem with its floor!

 

[Harry Bloomfield]

That looks like pitch has been poured on top of the concrete base, maybe even two layers of pitch?

 

[desertrose]

Hi @Harry Bloomfield - with apologies to the OP for the hijack, I would appreciate your thoughts on my post!

 

[^woody^]

It's common and normal for screed to detach around floor perimeters. A combination of several factors, the main ones being banging in the carpet grippers, poor screed adhesion at the edge, initial and seasonal floor slab movement and the frequent changes to the temperature at the floor edge.

 

[desertrose]

Noted, @^woody^, thank you. Mine seems to have crumbled into nearly sand (the corners are much worse). What would you do before using a self-levelling compound (you can see I'm removing some on the right hand side - it failed and separated)?

 

[^woody^]

Some sand and cement. Knock off any loose stuff and vacuum all the debris out. Wet it before filling and some PVA would help adhesion.

If not too difficult a perimeter of 10mm or so of polystyrene insulation may be better before filling, but if too much messing about, don't bother just fill it.

 

[desertrose]

Thanks very much @^woody^! Polystyrene insulation sounds like a good idea. Depending how easily the old screed comes up everywhere else, I might put an expansion strip all the way around against the uPVC as you can literally hear it expanding and contracting.