Burglars caused about £3,000 of damage when they stripped lead from the roof of the Hawthorn Family Support Centre, in East End Park, Leeds.
They left holes in the roof which allowed water to pour into the building, threw rubbish around the centre's back yard and smeared human waste onto a play area.
The building is relied upon by dozens of families who have someone with learning difficulties.
Fund-raiser Kate Grimshaw said: "It was a real kick in the teeth. They had caused about £3,000 in damage and left a real mess. We are fund-raising to keep the place open, so this was really hard for us."
Refit
Just six months ago, the centre, in Londesboro Terrace, had a grand re-opening ceremony after it won a £30,000 refit.
People voted overwhelmingly for the Hawthorn in a contest run by social housing contractor Connaught and Radio Aire.
Connaught fitted two new kitchens and new carpets, completed a full paint job, fixed the roof and worked on the heating and the plumbing, all without charge.
And it is Connaught again which has put its hand in its pocket, with bosses sending workers to the Hawthorn to repair the latest damage without charge.
Andy Green, Connaught's area director, said: "The staff who worked on the original job here got really into it. Everyone at the centre made a big impression on them, so we were really sorry to hear about the damage.
"We like to leave a lasting legacy, to get involved with the community, and were happy to help out again."
No lead is on the centre's roof now, as the damage has been repaired with a material called Ubiflex, which is similar to roofing felt.
"If this is taken off the roof it is worthless – it has no re-sale value whatsoever," Andy added.
Frank Plumbridge, Leeds Mencap's chief executive, said: "We can't thank Connaught enough. They have come to our help when we really needed it."
For details about the Hawthorn, or to make a donation, call 0113 2351331.
richard.edwards@ypn.co.uk