The invention relates to agricultural greenhouses made of plastic, with a layered coating made of polystyrol solair-extra and/or polyethylene foil, configured as a circular arc, circular arc with vertical, linear or aslope lateral sides, the greenhouses being meant especially for vegetables and horticultural crops as well as for covering yard pools. According to the invention, the greenhouses consist of a framework made of frames comprising beams () filled with polyurethane foam and supporting poles () filled with concrete, clamped at the joints of the beams with some T- and L-shaped connection pieces () filled, at the time of coupling, with foam, by means of the gaps (), joined by adding some spacers filled with foam and with some braces () alternately adhered on two rows, the greenhouses being provided, at the upper side, with tiltable windows (), at the ends having sliding doors () and, as a coating, they have minimum three layers of polystyrol solair-extra and/or polyethylene foil arranged in two or in three inflatable layers (), where the first solair-extra layers are positioned beneath and between the two rows of alternately intercalated spacers and are fixed by means of some PVC rods ().Invenţia se referă la sere agricole din material plastic, cu înveliş stratificat din polistyrol soler-extra sau/şi folie de polietilenă, configurate în formă de arc de cerc, arc de cerc cu laterale verticale, liniare sau în pantă, serele fiind destinate în principal culturilor legumicole şi horticole, precum şi la acoperirea piscinelor de curte. Serele conform invenţiei sunt constituite dintr-un schelet realizat din cadre compuse din grinzi () umplute cu spumă poliuretanică şi stâlpi () de susţinere umpluţi cu beton, prinşi la îmbinările grinzilor cu nişte piese de legătură () în formă de T şi L, umplute la momentul cuplajului cu spumă prin intermediul golurilor (), unite prin adăugarea unor distanţiere umplute cu spumă şi cu nişte montanţi () lipiţi alternativ pe două rânduri
