[Inkscape-user] Fill "only on one layer"

People,

I am trying to create a series of sketches to show changes to roof tressles (I want to create a wide manhole - see start of first sketch attached) but I have run into problems with adding a fill colour (as shading for the beams). It seems like it would be quicker and easier for me if I could get the fill action to fill on ONE layer instead of taking all of the lines for all the of layers into account - but this doesn't appear to work? - is it possible somehow?

Thanks,

Phil.