I have been in my house for 18 months. I have noticed a puddle of water at the base of my hallway wall 3 times - each incident has coincided with heavy rainfall so I am 100% sure it relates to the rain. I have had a roofing specialist in and having spent 20 minutes in my ceiling and up on the roof he can find no evidence of water coming from above - there is no damage to the gyprock of the walls and no signs of water staining on the roof insulation and the underside of the tiles is fully lined with that thick silver lining. My brother in law also got up into the roof space and found no signs of water coming from above. The hallway backs onto the two bathrooms but since both bathrooms get used regularly and the water puddles have occurred only 3 times over 18 months it cannot be related to leaking pipes. So can anyone come up with an explanation as to why/how I come to have water in my hallway after heavy rainfall but not coming from above (e.g. is is possible for rain to get into the house (but not from above) and run along the pipes?). We are all stumped.

A leak in the vent, near the bottom perhaps. Means opening the wall. You could go up on the roof with a hose.

What do you mean by vents? The roof is solid tile with lining directly under it with no signs of water leakage. Floor is solid concrete slab and there are only tiny vents running from outside of the house - too small to allow any qty of water in.

Plumbing vents, pipes that allow sewer gas to escape. They go straight up through the roof, or possibly up the side of the house, but ending past the roof. A leak would mean they are sealed improperly on the roof, usually.

I would think that with a tile roof, however, any water in the house probably is from a leak in the tiles. The trouble is it could be anywhere from the ridge down, dribbling down between the layers, so inspecting may require a lot of work. A roofer will tell you that but they are pretty good at finding them.