Hey Darren,
as Ricky says, that video should solve any degenerate face problems you are having. Try adding the noise a few times if it still doesn't export after the first time.
If it still doesn't export check the error to make sure it is still the same error - it could be an STL error (both errors look quite similar, but STL will be mentioned in the new one)
If it is still the same degenerate faces error try exporting all objects individually to find exactly which object(s) have problems (the walls, from what you say). You can just select all your objects, add them to the export list and export to see which ones have errors. If there are only a few it may be quickest to fix them manually.
Convert them to an editable mesh (rather than an editable poly) and press 3 to be able to select triangles. Select all the triangles of the mesh and detach them. This should leave you with all the degenerate faces (which are, in effect, just lines) and you can delete them. It is important to select triangle individually as dragging a selection box around multiples may also select degenerate faces hidden between faces. Whether this is quicker than remodelling as Ricky suggests will depend largely on the complexity of your model and how long it will take to select the triangles individually.
If you see the STL error then run the STL check script from the modifier stack and it should highlight any faces that are causing errors. Often these can just be deleted, but may need to be remodelled, depending on model
Hope that helps
Cheers
Jules