I thought there used to be like a button or two you pressed with the keyboard that would work on getting rid of all tri’s… I’ve searched but I’m sure I’m not using correct keywords 
anyone give me a hint please 
Hi, select the faces you want to convert. Press space bar>Edit>Faces>Convert to quads.
Alternatively, select faces then press ALT+J.
Sonix.
oooh thanks much sonix!
oh and just as an FYI for all the n00bies…
doing this on a mesh imported from terragen will take like 20 minutes! haha
You’re welcome. Selecting sections of the faces in the mesh and converting will take less time than trying to do the whole mesh in one go. 
Sonix.
depending on the mesh, trying to get back to a grid from a bunch of triangles is a pain, alt+j is much better suited for only a few triangles at a time
oh, and if you want a technically correct, but not semantically* correct answer, turning on subsurf makes all quads…
- I can’t think of better word to use there