Setting of liabilities against zakaat

i usually pay my wifes Zakaah for her annually (after taking her permission). I do not owe zakaah for myself as i do not have much Zakaatable assets as well due to the loan (12x payments) on our house which is in my name and for which i pay for. As both of us are staying at the house, is it permissible to set off the loan against her zakaatable assets as well (do a combined zakaah calculation)?