a joint - sealing , strip 1 is shown and described first with respect to fig1 to 3 , such strip consisting of a soft , porous foam material , which is provided with an impregnation leading to delayed recovery . the impregnation is carried out based on polywax , which only contains a small component of modifying substances which , in terms of volume , have no bearing . of importance is that the impregnation is carried out in one marginal longitudinal area 2 or 3 of the joint - sealing strip . the cross section of the joint - sealing strip 1 shown in fig1 and 2 shows that the marginal longitudinal area 2 or 3 extends over the total thickness &# 34 ; d &# 34 ; of the joint - sealing strip 1 , but not over the total width &# 34 ; b &# 34 ;. in the exemplified embodiment , a width &# 34 ; b 1 &# 34 ; of the -- only -- impregnated marginal longitudinal area 2 or 3 rather amounts to only about one fourth part of the total width &# 34 ; b &# 34 ; of the joint - sealing strip 1 . furthermore , the cross - sectional representation according to fig1 or fig3 shows that following the release of recovery , a rising ( flank 4 or 5 ) profile is obtained toward a longitudinal center line a ( or the corresponding vertical longitudinal center plane ), starting from a marginal longitudinal area 2 or 3 . in the embodiment according to fig1 to 3 , in which provision is made for two impregnated marginal longitudinal areas 2 , 3 , an overall bell - shaped profile ( in the upper zone ) of the joint - sealing strip 1 is obtained shortly upon the release of recovery . a center zone 6 of the joint - sealing strip 1 , which is not impregnated with an impregnating medium leading to delayed recovery , spontaneously recovers immediately upon the release of recovery . therefore , the shown and described bell - like profile is obtained due to the fact that the marginal longitudinal areas 2 , 3 did not recover . it is important , furthermore , that a thickness &# 34 ; d1 &# 34 ; of the completely recovered joint - sealing strip 1 ( fig2 ) amounts to only about two to three times the thickness &# 34 ; d2 &# 34 ; of the joint - sealing strip 1 in the compressed state . fig4 shows the profile of a joint - sealing strip 1 , in connection with which only one marginal longitudinal area 3 &# 39 ; is provided with an impregnating medium leading to delayed recovery . here , a profile is obtained that is , overall , substantially wedge - shaped . in fig5 the joint - sealing strip 1 according to the design according to fig1 to 3 is shown in the installed condition , whereby complete recovery of the impregnated marginal longitudinal areas 2 , 3 has not yet occurred . fig5 shows that the recovery profile of the center zone 6 results with respect to installation in an advantageous first complete sealing of a joint 7 between two brickwork corner zones 8 , 9 or the like . it shows , furthermore , that the joint - sealing strip 1 is provided on one of its surfaces of width with an adhesive tape 10 , as it is known per se . in said exemplified embodiment , the joint - sealing strip 1 is glued to the one brickwork surface 11 of the brickwork corner zone 9 by means of the adhesive tape 10 . following complete recovery of the joint - sealing strip 1 also in the marginal longitudinal areas 2 , 3 , an advantageous , quasi three - layer structure is obtained in the direction of thickness of the joint - sealing strip 1 , i . e ., from a top side 12 ( in the installed condition ) to a bottom side 13 . such a layered structure is important and advantageous under the aspect of construction physics as well . higher tightness is obtained in the marginal longitudinal areas 2 , 3 , as well as very extensive closure of the pores of the foam material . on the other hand , a certain permeability including permeability to vapor remains available in the center area 6 of the joint - sealing strip 1 . while a certain discharge of vapor from the interior of the sealed construction is still possible also through the brickwork 8 -- in the installed condition according to fig4 such discharge from the inside quasi &# 34 ; bypassing &# 34 ; the lower marginal area 2 , thus in the direction of the surface 12 --, a quasi double barrier is obtained on account of the two marginal longitudinal areas 2 , 3 with respect to penetration of moisture or vapor from the outside . furthermore , it is preferred that the impregnation of the two marginal longitudinal areas 2 , 3 differs , in a way such that the marginal longitudinal area 3 , the latter being arranged facing the outer side of a building in the installed condition , permits a diffusion of water vapor to a higher degree than the impregnation of the marginal longitudinal area 2 arranged facing the interior of the building in the installed condition . the same result can be achieved also by providing one ( or both ) marginal longitudinal areas 2 , 3 with an impregnation in a different concentration , in a way such that the concentration of the outer surface 12 or 13 decreases toward a center zone 6 of the joint - sealing strip 1 , whereby said measure may be implemented additionally as well . fig6 shows an installation clearance -- also still shortly after the release of the delayed recovery -- with respect to an only unilateral impregnation in a marginal longitudinal area or the joint - sealing strip 1 . due to the wedge - shaped profile of the cross section , a very good installation possibility is obtained in this case as well . fig5 and 6 each shown also by the shaded representation the nature of the surfaces 12 and 13 following complete recovery of the impregnated marginal longitudinal areas 2 and 3 , respectively . fig7 shows the structure of the polyurethane foam material used in the present case . the structure of the foam material , which is shown here slightly schematically for technical drawing reasons , consists of a net - like basic structure , in which the pores 14 , 15 , 16 etc . are present , such pores have larger or smaller openings . although the cross sections of the openings of the pores are shown comparatively large , closure of the foam material is substantially obtained in fact also by the arrangement of very many layers of relatively small pores one on top of the other . for example , when simply blowing at the material , a passage of air through the latter can be accomplished only with great effort . this conforms to the measured technical value of about 40 to 50 l . sq . m . s specified in the foregoing . the special impregnating medium used is advantageous in that it has an extremely low surface tension . therefore , it already penetrates the marginal longitudinal areas during simple soaking . this may be of significance even in that the foam material may have a certain closed structure with a lesser percent proportion of open pores , because said special impregnating medium easily penetrates the foam material . the above description of the exemplified embodiment is based on the assumption that a center area of the foam material is not impregnated at all . however , practically the same results are obtained if , as described in the foregoing for the first variation , a conventional joint - sealing strip -- that is impregnated for delayed recovery in the conventional way as well -- is additionally or in a special way impregnated in one or both marginal longitudinal area ( s ) 2 , 3 . the features of the invention disclosed in the above specification , the drawing and in the claims may be significant to the realization of the invention both individually and in any desired combination . all disclosed features are significant to the invention . the content of the disclosure of the associated / attached priority documents ( copy of the earlier application ) is hereby included to its fullest extent in the disclosure of the present application .