Non-destructive wall thickness and composition

Vkrzalic · 10-18-2009, 10:20 AM

Hi All!

I have one question that I hope that You can find the answer for:
How to non-destructively find out the composition of a finished concrete/brick wall?
For an example, we are making different sorts of stainless steel terraces, stairways, fences etc. that frequently need to be fixed to the already finished walls or stairways made of conrete and/or bricks (both hollow and solid form).
The problem is that we never know what is hidden beneath the mortar and often you realize the right composition of wall is when you drill the holes for fixing the stairway, just to discover that nothing is there except the thin layer of mortar and rubble behind it.
Is there some sort of device that could tell us the right density (or other information) that could be used to see the exact composition of the wall?
Ultrasound does here little help as it bounes of the air hidden below ceramic tiles in places that has no glue and it's rather inacurate device to "see" through the wall.

Any sort of pointing to manufacturers, literature or information would be more than welcome.

Thank you!

Cork-Guy · 10-18-2009, 12:16 PM

This is an interesting question; however, the cost of the equipment to do such this task would most likely be more than the repairs itself

mudmixer · 10-18-2009, 05:52 PM

In Serbia, it is likely you are dealing with either hollow (multi-cell) clay block or just solid walls depending on the age of the structure). If is is very old, you could find a solid wall. It is difficult to tell since both walls are are very solid and hard because of the plaster covering on the walls.

Drilling a small hole will give you a clue of the material in the wall (clay block will be reddish and in some areas yellowish and concrete will be gray). The drilling rate and ease should tell you something about whether is is hollow or solid. Many walls are either solid concrete or solid masonry depending on the age.

Since you are dealing with permanent structures, it is not as easy as people in the U.S. that are more acustomed to dealing with more temporary wood framing.

How old is the building and what do you know about the other buildings in the area? If it is an apartment or flat that is a building over 3 stories, the wall may be concrete. Tito built a lot of Russian-style precast plants after 1945. If it was built between 1960 and 1985, I could be gas concrete (Ytong type) that is solid, but easy to drill into.

Around stairways, you could find a variety of different materials or construction methods.

Dick

Vkrzalic · 10-19-2009, 05:09 AM

Thank You guys!

@mudmixer
Yup.. you could drill a sample hole in wall in order to see what is beyond, but there are some places where drilling is simply not possible or it may take a lot of drilling in order to find the best place to put fixtures or support pillars for staircases. Also, it would be nice to somehow screen the range of available places for putting the pillars and to see where it would be more convenient.

You are also right about the ages and possible bulding material. We are facing now with different story here. A majority of houses are private built, with no available documentation (plans and cross sections) and of course, there are always construction worker who are not always building according to blueprints.

Anyway... this remains as really interesting question as it is not only problem for me, but a whole lot of repairman and friends who work on installation jobs face the similar problems.
Something like finding the wires in the wall... but more delicate