SHEBOYGAN, Wis.(WHBL) - Sheboygan firefighters battled a stubborn attic fire and the ongoing heat wave last night.  The fire at 1527 North 11^th Street was discovered about 9 o’clock and left two families homeless, at least for the night.  Shift Commander Keith Risse said the upstairs occupant discovered the fire when she saw flames and smoke coming through a vent.  Risse said firefighters arrived on the scene and safely removed three cats from the upper apartment.  They then had to pull down the ceiling and insulation to get at the blaze.  Risse said both tenants were displaced from the residence because of the damage and due to utilities being shut off.  The Red Cross assisted one of them with accommodations for the evening.  Damage is estimated at $15,000 and there's no word on the cause.  Risse said firefighters remained on the scene into the early morning hours.