Where the surface finish is dot 'n' dab, then it's most likely that your wall construction is an outer skin of brick or stone, then an air gap probably filled with insulation, then an inner skin of brick or more likely some kind of block work such as aerated- or breeze-block.
For those unfamiliar with the term dot 'n' dab: The options then to make the final finish are either wet plaster comprising of a base coat plus top coat skim, or plasterboard sheets fixed in place with blobs of plasterboard adhesive dotted across the wall, then the board pushed on to the adhesive. This latter is dot 'n' dab.
After the joints have been taped and skimmed, the result is a smooth wall finish that was quicker to apply and used less materials than a traditional wet plaster finish. Dot 'n' dab is useful where there's an uneven wall surface such as rough brickwork or for where there's a need to square up the room because the the block work means that the opposite walls are not parallel.
The catch is that there are gaps between the back of the board and the wall in the spaces between the adhesive blobs. Where these gaps occur, the board surface can't support much pressure from a wall fixing. A traditional wall plug and screw through to the block behind will collapse the board in to the unsupported gap.
@lost0ne33 - depending partly on what's being hung, you have a couple of options.
The plasterboard between the adhesive blobs will be quite strong so long as you're not fixing on a joint. Gripit fixings can be used where a flat TV bracket or one with a small amount of tilt is to be hung. Once in place, most of the TV's weight is acting vertically so the fixings aren't going to move. If you decide to go with Gripits then you'll use them where there's a gap behind the board because of the way it anchors. (Once you see the wing design then this will make sense.) It's unlikely though that every fixing point will hit a gap if you're spreading the load evenly. This means you will inevitably hit a point where the board is sitting over a solid blob of adhesive. At these point use a basic wall plug and screw fixing as if you are fixing through plaster directly over brick.
For brackets that involve an articulated arm then the loading is more complex. You need something that will withstand a lot of pull and push force acting in the direction of the fixing. You also need a fixing that will transfer the weight to the block behind so that the board surface doesn't collapse in. In effect, the fixings become pilings sitting just slightly proud of the board surface. A good solution for this is Rigifix. Use the M6 size. They are more than sufficient for hanging over 100Kg. Don't be tempted to use the M8 size. They're overkill for a TV mount, even for a full motion bracket.
