I have a customer who wants WiFi but the house is quite large and there is foil backed insulation which blocks any RF signal, so it looks like I may have to install a WiFi router in each room, should I have all the routers using the same SSID but different channels or is there is a better way to do this?
Your approach is correct.
The “problem” in this is the user equipment. It really depaneds on how it will beahve. I have seen iPhones (especially iPhones) refusing to disattach from the “weak” AP, and refusing to conenct to the more stronger, which is say 3 meters away (and the weak one in 1 floor down, behind a concrete floor).
Maybe an more “active” system as Ubiquity Unifi would be nice. If you install three AP’s, then they “manage” themselves between each other the channel spacing, de-assosiation of clients etc… In other words: the AP will actively “kick out” the weak iPhone, and will force it to use the stronger AP.
It can be done with or without a controller.
Haik
P.S. Of course, this applies to any phone / tablet etc… Not only iPhones.
If the insulation is strong enough to block RF between rooms, then you should be ok to use the same SSID across multiple APs. Most home users are fairly stationary in their WiFi usage patterns, but for the occasional movers, you could see issues as you transition from room to room. TCP based apps will recover easily enough, but VoIP applications may see some packet loss.
It really all depends on what the usage is going to be and what amount of interruption is acceptable when transitioning between APs / Rooms.
Many thanks for the replies, It is pity that the device will not connect to the strongest signal but remain connected until signal is lost and then search for the strongest signal?
If you put multiple routers in, I would also suggest adjusting the power level of each AP to minimize bleed over. You can also use an Access List rule like the following to tell the router to only let clients connect within a specific signal range.
/interface wireless access-list
add interface=wlan1 signal-range=-80..120
add authentication=no forwarding=no
This rule says that any wireless client with a signal between -80 and 120 CAN connect.
Since the rules are processed in order, the second rule says drop all other wireless connections.
These types of rules can work very well, but they have to be fine tuned. Dropping them in without spending the time to fine tune will lead lots of frustration.
I can also confirm this for almost any “old” android device (2.x and older) … tested with a bunch of HTC (desire*, wildfire*, …) and Samsung phones (S1, S2, Ace, …). Works fine with my current S4 
if anyone has the new iPhone (5c, 5s) please test and report.
JF