I'm no real expert, it took me a few tries to get these results, so i thought i'd share my findings. If you want to make hand drawn style dungeon floorplans. It can be used for other purposes too.
Step 1.: You make a new document in whatever size. And make the paper/parchment/canvas background in whatever way you want (in this image i used the technique where you make a layer>Filter>Render>Clouds with black&white colors; then make it Filter>Stylize>Emboss; then Image>Adjustments>Hue/saturation ticking the colorize option. Paper-like bg done)
Step 2.: Duplicate the background.
Step 3.: You need to make a pattern, with any style filling (i made the short parallel lines in a group of 5-7, then put next to eachother in different angles; all of it in a 300x300 pixels document; then Edit>Make Pattern...)
Step 4.: Make the pattern adjustment layer with the style of pattern you just made before. (This layer goes between the original paper bg and the bg copy) Now you see all the document patterned. Click on the layer mask, hit Ctrl+I, now the pattern is invisible, just leave it for now.
Step 5.: Now this is where it gets interesting. This is the bg copy layer. Add a mask to this layer. Then go to the layer style (blending options) panel. 1st effect is an inner glow with an Overlay blend mode, color is black, size is whatever you like. 2nd effect is a pattern overlay (whatever you want to use as a floor pattern) with a Color burn blend mode, opacity what you like, size as you see it fit. 3rd effect is a stroke, with an Overlay blend mode, position outside, size what you like (i used 2) and color is black. Style done, save it if you want.
Step 6.: Now you can paint your dungeon or house or building on the layer masks. The pattern fill layer is for the wall texture, the styled layer is for the floorplan itself.
I find it easy to use, i just need to save the layer styles, if i want to use them on a regular basis.
I hope it's useful.